Signed-off-by: NMichael Opdenacker <michael@free-electrons.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Currently we scale the mempool sizes depending on memory installed
in the machine, except for the bio pool itself which sits at a fixed
256 entry pre-allocation.

There's really no point in "optimizing" this OOM path, we just need
enough preallocated to make progress. A single unit is enough, lets
scale it down to 2 just to be on the safe side.

This patch saves ~150kb of pinned kernel memory on a 32-bit box.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Some targets can return both valid data and sense information.
Always update the request data_len from the SCSI command residual.
Callers should interpret sense data to determine what parts of the
data are valid in case of a CHECK CONDITION status.
Signed-off-by: NPete Wyckoff <pw@osc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

This patch enhances SCSI error printing by:

 - Making use of scsi_print_result() in the completion functions.

 - Having scmd_printk() output the disk name (when applicable).
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.
Signed-off-by: NRobert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: NJoel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The KM_BIO_SRC_IRQ kmap slot must be taken with local irqs disabled.  Add a
check into scsi for this.

Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

scsi_retry_command only has a single caller, so there is no point
in having this function.  Additionally the memset of the sense
buffer it does is entirely superflous as scsi_request_fn already
calls scsi_init_cmd_errh to perform this memset before the command
is reissued.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

We have full flexibility of merging parameters now, so we can remove the
hooks that define back/front/request merge strategies. Nobody is using
them anymore.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

It's a file system thing, for block requests the only size used in the
io paths is ->data_len as it is in bytes, not sectors.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

	#!/bin/sh
	#
	# Replace one string by another in all the kernel sources.
	#

	set -e

	for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
		quilt add $file
		sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
		mv /tmp/$$ $file
		quilt refresh
	done

The script was run like this

	sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch contains the needed changes to the scsi-ml for the target
mode support.

Note, per the last review we moved almost all the fields we added
to the scsi_cmnd to our internal data structure which we are going
to try and kill off when we can replace it with support from other
parts of the kernel.

The one field we left on was the offset variable. This is needed to handle
the case where the target gets request that is so large that it cannot
execute it in one dma operation. So max_secotors or a segment limit may
limit the size of the transfer. In this case our tgt core code will
break up the command into managable transfers and send them to the
LLD one at a time. The offset is then used to tell the LLD where in
the command we are at. Is there another field on the scsi_cmd for
that?
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

ATAPI devices transfer fixed number of bytes for CDBs (12 or 16).  Some
ATAPI devices choke when shorter CDB is used and the left bytes contain
garbage.  Block SG_IO cleared left bytes but SCSI SG_IO didn't.  This patch
makes SCSI SG_IO clear it and simplify CDB clearing in block SG_IO.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Mathieu Fluhr <mfluhr@nero.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Douglas Gilbert <dougg@torque.net>
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Cc: <stable@kernel.org>
Acked-by: NJeff Garzik <jgarzik@pobox.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I wanted to add some BUG checks to scsi_prep_fn to make sure no one
sends us a non-sg command, but this function is a horrible mess.

So I decided to detangle the function and document what the valid
cases are.  While doing that I found that REQ_TYPE_SPECIAL commands
aren't used by the SCSI layer anymore and we can get rid of the code
handling them.

The new structure of scsi_prep_fn is:

 (1) check if we're allowed to send this command
 (2) big switch on cmd_type.  For the two valid types call into
     a function to set the command up, else error
 (3) code to handle error cases

Because FS and BLOCK_PC commands are handled entirely separate after
the patch this introduces a tiny amount of code duplication.  This
improves readabiulity though and will help to avoid the bidi command
overhead for FS commands so it's a good thing.

I've tested this on both sata and mptsas.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

In scsi_execute_async()'s error path, a struct scsi_io_context
allocated with kmem_cache_alloc() is kfree()'d. Obviously
kmem_cache_free() should be used instead.
Signed-off-by: NArne Redlich <arne.redlich@xiranet.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Right now ->flags is a bit of a mess: some are request types, and
others are just modifiers. Clean this up by splitting it into
->cmd_type and ->cmd_flags. This allows introduction of generic
Linux block message types, useful for sending generic Linux commands
to block devices.
Signed-off-by: NJens Axboe <axboe@suse.de>

Attached is a patch that should limit a possible recursion that can
lead to a stack overflow like follows:

Kernel stack overflow.
CPU:    3    Not tainted
Process zfcperp0.0.d819
(pid: 13897, task: 000000003e0d8cc8, ksp: 000000003499dbb8)
Krnl PSW : 0404000180000000 000000000030f8b2 (get_device+0x12/0x48)
Krnl GPRS: 00000000135a1980 000000000030f758 000000003ed6c1e8 0000000000000005
           0000000000000000 000000000044a780 000000003dbf7000 0000000034e15800
           000000003621c048 070000003499c108 000000003499c1a0 000000003ed6c000
           0000000040895000 00000000408ab630 000000003499c0a0 000000003499c0a0
Krnl Code: a7 fb ff e8 a7 19 00 00 b9 02 00 22 e3 e0 f0 98 00 24 a7 84
Call Trace:
([<000000004089edc2>] scsi_request_fn+0x13e/0x650 [scsi_mod])
 [<00000000002c5ff4>] blk_run_queue+0xd4/0x1a4
 [<000000004089ff8c>] scsi_queue_insert+0x22c/0x2a4 [scsi_mod]
 [<000000004089779a>] scsi_dispatch_cmd+0x8a/0x3d0 [scsi_mod]
 [<000000004089f1ec>] scsi_request_fn+0x568/0x650 [scsi_mod]
...
 [<000000004089f1ec>] scsi_request_fn+0x568/0x650 [scsi_mod]
 [<00000000002c5ff4>] blk_run_queue+0xd4/0x1a4
 [<000000004089ff8c>] scsi_queue_insert+0x22c/0x2a4 [scsi_mod]
 [<000000004089779a>] scsi_dispatch_cmd+0x8a/0x3d0 [scsi_mod]
 [<000000004089f1ec>] scsi_request_fn+0x568/0x650 [scsi_mod]
 [<00000000002c5ff4>] blk_run_queue+0xd4/0x1a4
 [<000000004089fa9e>] scsi_run_host_queues+0x196/0x230 [scsi_mod]
 [<00000000409eba28>] zfcp_erp_thread+0x2638/0x3080 [zfcp]
 [<0000000000107462>] kernel_thread_starter+0x6/0xc
 [<000000000010745c>] kernel_thread_starter+0x0/0xc
<0>Kernel panic - not syncing: Corrupt kernel stack, can't continue.

This stack overflow occurred during tests on s390 using zfcp.
Recursion depth for this panic was 19.

Usually recursion between blk_run_queue and a request_fn is avoided
using QUEUE_FLAG_REENTER. But this does not help if the scsi stack
tries to flush the starved_list of a scsi_host.

Limit recursion depth when flushing the starved_list
of a scsi_host.
Signed-off-by: NAndreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Currently struct scsi_cmnd has various fields that are used to backup
original data after the corresponding fields have been overridden for
EH commands.  This means drivers can easily get at it and misuse it.
Due to the old_ naming this doesn't happen for most of them, but two
that have different names have been used wrong a lot (see previous
patch).  Another downside is that they unessecarily bloat the scsi_cmnd
size.

This patch moves them onstack in scsi_send_eh_cmnd to fix those two
issues aswell as allowing future EH fixes like moving the EH command
submissions to use SG lists like everything else.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

There was a logic fault in scsi_io_completion() where zero transfer
commands that complete successfully were sent to the block layer as
not up to date.  This patch removes the if (good_bytes > 0) gate
around the successful completion, since zero transfer commands do have
good_bytes == 0.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

If a device gets offlined as a result of the Inquiry sent
during scanning, the following oops can occur. After the
disk gets put into the SDEV_OFFLINE state, the error handler
sends back the failed inquiry, which wakes the thread doing
the scan. This starts a race between the scanning thread
freeing the scsi device and the error handler calling
scsi_run_host_queues to restart the host. Since the disk
is in the SDEV_OFFLINE state, scsi_device_get will still
work, which results in __scsi_iterate_devices getting
a reference to the scsi disk when it shouldn't.

The following execution thread causes the oops:

CPU 0 (scan)				CPU 1 (eh)

---------------------------------------------------------
scsi_probe_and_add_lun
                        ....
                                        scsi_eh_offline_sdevs
                                        scsi_eh_flush_done_q
scsi_destroy_sdev
scsi_device_dev_release
                                        scsi_restart_operations
                                         scsi_run_host_queues
                                          __scsi_iterate_devices
                                           get_device
scsi_device_dev_release_usercontext
                                          scsi_run_queue
                                            <---OOPS--->

The patch fixes this by changing the state of the sdev to SDEV_DEL
before doing the final put_device, which should prevent the race
from occurring.

Original oops follows:

Badness in kref_get at lib/kref.c:32
Call Trace:
[C00000002F4476D0] [C00000000000EE20] .show_stack+0x68/0x1b0 (unreliable)
[C00000002F447770] [C00000000037515C] .program_check_exception+0x1cc/0x5a8
[C00000002F447840] [C00000000000446C] program_check_common+0xec/0x100
 Exception: 700 at .kref_get+0x10/0x28
    LR = .kobject_get+0x20/0x3c
[C00000002F447B30] [C00000002F447BC0] 0xc00000002f447bc0 (unreliable)
[C00000002F447BB0] [C000000000254BDC] .get_device+0x20/0x3c
[C00000002F447C30] [D000000000063188] .scsi_device_get+0x34/0xdc [scsi_mod]
[C00000002F447CC0] [D0000000000633EC] .__scsi_iterate_devices+0x50/0xbc [scsi_mod]
[C00000002F447D60] [D00000000006A910] .scsi_run_host_queues+0x34/0x5c [scsi_mod]
[C00000002F447DF0] [D000000000069054] .scsi_error_handler+0xdb4/0xe44 [scsi_mod]
[C00000002F447EE0] [C00000000007B4E0] .kthread+0x128/0x178
[C00000002F447F90] [C000000000025E84] .kernel_thread+0x4c/0x68
Unable to handle kernel paging request for <7>PCI: Enabling device: (0002:41:01.1), cmd 143
data at address 0x000001b8
Faulting instruction address: 0xd0000000000698e4
sym1: <1010-66> rev 0x1 at pci 0002:41:01.1 irq 216
sym1: No NVRAM, ID 7, Fast-80, LVD, parity checking
sym1: SCSI BUS has been reset.
scsi2 : sym-2.2.2
cpu 0x0: Vector: 300 (Data Access) at [c00000002f447a30]
    pc: d0000000000698e4: .scsi_run_queue+0x2c/0x218 [scsi_mod]
    lr: d00000000006a904: .scsi_run_host_queues+0x28/0x5c [scsi_mod]
    sp: c00000002f447cb0
   msr: 9000000000009032
   dar: 1b8
 dsisr: 40000000
  current = 0xc0000000045fecd0
  paca    = 0xc00000000048ee80
    pid   = 1123, comm = scsi_eh_1
enter ? for help
[c00000002f447d60] d00000000006a904 .scsi_run_host_queues+0x28/0x5c [scsi_mod]
[c00000002f447df0] d000000000069054 .scsi_error_handler+0xdb4/0xe44 [scsi_mod]
[c00000002f447ee0] c00000000007b4e0 .kthread+0x128/0x178
[c00000002f447f90] c000000000025e84 .kernel_thread+0x4c/0x68
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

We have to be able to remove SCSI devices even when they are suspended, so
QUIESCE -> CANCEL must be a legal state transition.  This patch (as727)
adds the transition to the state machine.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

This patch simplifies "good_bytes" computation in sd_rw_intr().
sd: "good_bytes" computation is always done in terms of the resolution
of the device's medium, since after that it is the number of good bytes
we pass around and other layers/contexts (as opposed ot sd) can translate
that to their own resolution (block layer:512).  It also makes
scsi_io_completion() processing more straightforward, eliminating the
3rd argument to the function.

It also fixes a couple of bugs like not checking return value,
using "break" instead of "return;", etc.

I've been running with this patch for some time now on a
test (do-it-all) system.
Signed-off-by: NLuben Tuikov <ltuikov@yahoo.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

With Achim patch the last user (gdth) is switched away from scsi_request
so we an kill it now.  Also disables some code in i2o_scsi that was
broken since the sg driver stopped using scsi_requests.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Use ARRAY_SIZE macro instead of sizeof(x)/sizeof(x[0]) and remove
duplicates of the macro.
Signed-off-by: NTobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

The calculation of nr_pages in scsi_req_map_sg() doesn't account for
the fact that the first page could have an offset that pushes the end
of the buffer onto a new page.
Signed-off-by: NBryan Holty <lgeek@frontiernet.net>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

libata needs to invoke EH without scmd.  This patch adds
shost->host_eh_scheduled to implement such behavior.

Currently the only user of this feature is libata and no general
interface is defined.  This patch simply adds handling for
host_eh_scheduled where needed and exports scsi_eh_wakeup() to
modules.  The rest is upto libata.  This is the result of the
following discussion.

http://thread.gmane.org/gmane.linux.scsi/23853/focus=9760

In short, SCSI host is not supposed to know about exceptions unrelated
to specific device or command.  Such exceptions should be handled by
transport layer proper.  However, the distinction is not essential to
ATA and libata is planning to depart from SCSI, so, for the time
being, libata will be using SCSI EH to handle such exceptions.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Some pioneer DVDs are apparently returning odd "not ready" status
codes that the mid-layer doesn't recognise and so passes back to the
user as errors.

This patch overhauls our not-ready handling and adds transparent retries for:

format in progress
rebuild in progress
recalculation in progress
operation in progress
Long write in progress
self test in progress

The Pioneer was actually returning "long write in progress"
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsi_lib.c: In function `scsi_kmap_atomic_sg':
drivers/scsi/scsi_lib.c:2394: warning: unsigned int format, different type arg (arg 3)
drivers/scsi/scsi_lib.c:2394: warning: unsigned int format, different type arg (arg 4)
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

The current dc395x driver uses PIO to transfer up to 4 bytes which do not
get transferred by DMA (under unclear circumstances). For this the driver
uses page_address() which is broken on highmem. Apart from this the
actual calculation of the virtual address is wrong (even without highmem).
So, e.g., for reading it reads bytes from the driver to a wrong address
and returns wrong data, I guess, for writing it would just output random
data to the device.

The proper fix, as suggested by many, is to dynamically map data using
kmap_atomic(page, KM_BIO_SRC_IRQ) / kunmap_atomic(virt). The reason why it
has not been done until now, although I've done some preliminary patches
more than a year ago was that nobody interested in fixing this problem was
able to reliably reproduce it. Now it changed - with the help from
Sebastian Frei (CC'ed) I was able to trigger the PIO path. Thus, I was
also able to test and debug it.

There are 4 cases when PIO is used in dc395x - data-in / -out with and
without scatter-gather. I was able to reproduce and test only data-in with
and without SG. So, the data-out path is still untested, but it is also
somewhat simpler than the data-in. Fredrik Roubert (also CC'ed) also had
PIO triggering on his system, and in his case it was data-out without SG.
It would be great if he could test the attached patch on his system, but
even if he cannot, I would still request to apply the patch and just wait
if anybody cries...

Implementation: I put 2 new functions in scsi_lib.c and their declarations
in scsi_cmnd.h. I exported them without _GPL, although, I don't feel
strongly about that - not many drivers are likely to use them. But there
is at least one more - I want to use them in tmscsim.c. Whether these are
the right files for the functions and their declarations - not sure
either. Actually, they are not scsi-specific, so, might go somewhere
around other scattergather magic? They are not platform specific either,
and most SG functions are defined under arch/*/... As these issues were
discussed previously there were some more routines suggested to manipulate
scattergather buffers, I think, some of them were needed around
crypto code... So, might be a common place reasonable, like
lib/scattergather.c? I am open here.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

scsi_kill_request() completes requests via normal SCSI completion path
which decrements busy counts; however, requests which get passed to
scsi_kill_request() aren't holding busy counts and scsi_kill_request()
don't increment them before invoking completion path resulting in
incorrect busy counts.  Bump up busy counts before invoking completion
path.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Modify well over a dozen mempool users to call mempool_create_slab_pool()
rather than calling mempool_create() with extra arguments, saving about 30
lines of code and increasing readability.
Signed-off-by: NMatthew Dobson <colpatch@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This complements the scsi_mode_sense() function
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

In order to use the new execute_in_process_context() API, you have to
provide it with the work storage, which I do in SCSI in scsi_device and
scsi_target, but which also means that we can no longer queue up the
target reaps, so instead I moved the target to a state model which
allows target_alloc to detect if we've received a dying target and wait
for it to be gone.  Hopefully, this should also solve the target
namespace race.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Regardless what mode page was asked for, Initio INIC-14x0 and
INIC-2430 always return page 6 without mode page headers.  Try to
recognise this as a special case in scsi_mode_sense and setting the
mode sense headers accordingly.
Signed-off-by: NAl Viro <viro@ftp.linux.org.uk>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Change the core SCSI code to use kzalloc rather than kmalloc+memset
where possible.
Signed-off-by: NJes Sorensen <jes@sgi.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Fix up an off by one error in calculating retries for scsi
commands. This bug was discovered when an SG_IO request
was sent to scsi core with retries = 0, causing the overall
timeout check to go off in scsi_softirq_done.
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

We have several points in the SCSI stack (primarily for our device
functions) where we need to guarantee process context, but (given the
place where the last reference was released) we cannot guarantee this.

This API gets around the issue by executing the function directly if
the caller has process context, but scheduling a workqueue to execute
in process context if the caller doesn't have it.  Unfortunately, it
requires memory allocation in interrupt context, but it's better than
what we have previously.  The true solution will require a bit of
re-engineering, so isn't appropriate for 2.6.16.
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

When the scsi_execute_async interface was added it ended up reducing
the flexibility of userspace to send arbitrary scsi commands through
sg using SG_IO. The SG_IO interface allows userspace to specify the
CDB length. This is now ignored in scsi_execute_async and it is
guessed using the COMMAND_SIZE macro, which is not always correct,
particularly for vendor specific commands. This patch adds a cmd_len
parameter to the scsi_execute_async interface to allow the caller
to specify the length of the CDB.
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

LLDDs should never see REQ_BLOCK_PC requests, we can handle them just
fine in the core code.  There is a small behaviour change in that some
check in sr's rw_intr are bypassed, but I consider the old behaviour
a bug.

Mike found this cleanup opportunity and provdided early patches, so all
the credit goes to him, even if I redid the patches from scratch beause
that was easier than forward-porting the old patches.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

This patch moves the SCSI softirq handling to the block layer version.
There should be no functional changes.
Signed-off-by: NJens Axboe <axboe@suse.de>