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  1. 23 12月, 2009 1 次提交
    • S
      kfifo: move struct kfifo in place · 45465487
      由 Stefani Seibold 提交于 
      This is a new generic kernel FIFO implementation.

The current kernel fifo API is not very widely used, because it has to
many constrains.  Only 17 files in the current 2.6.31-rc5 used it.
FIFO's are like list's a very basic thing and a kfifo API which handles
the most use case would save a lot of development time and memory
resources.

I think this are the reasons why kfifo is not in use:

 - The API is to simple, important functions are missing
 - A fifo can be only allocated dynamically
 - There is a requirement of a spinlock whether you need it or not
 - There is no support for data records inside a fifo

So I decided to extend the kfifo in a more generic way without blowing up
the API to much.  The new API has the following benefits:

 - Generic usage: For kernel internal use and/or device driver.
 - Provide an API for the most use case.
 - Slim API: The whole API provides 25 functions.
 - Linux style habit.
 - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros
 - Direct copy_to_user from the fifo and copy_from_user into the fifo.
 - The kfifo itself is an in place member of the using data structure, this save an
   indirection access and does not waste the kernel allocator.
 - Lockless access: if only one reader and one writer is active on the fifo,
   which is the common use case, no additional locking is necessary.
 - Remove spinlock - give the user the freedom of choice what kind of locking to use if
   one is required.
 - Ability to handle records. Three type of records are supported:
   - Variable length records between 0-255 bytes, with a record size
     field of 1 bytes.
   - Variable length records between 0-65535 bytes, with a record size
     field of 2 bytes.
   - Fixed size records, which no record size field.
 - Preserve memory resource.
 - Performance!
 - Easy to use!

This patch:

Since most users want to have the kfifo as part of another object,
reorganize the code to allow including struct kfifo in another data
structure.  This requires changing the kfifo_alloc and kfifo_init
prototypes so that we pass an existing kfifo pointer into them.  This
patch changes the implementation and all existing users.

[akpm@linux-foundation.org: fix warning]
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      45465487
  3. 17 12月, 2009 1 次提交
  5. 16 12月, 2009 2 次提交
  7. 13 12月, 2009 4 次提交
    • A
      [SCSI] 3w-9xxx fix bug in sgl loading · 53ca3535
      由 adam radford 提交于 
      This small patch fixes a bug in the 3w-9xxx driver where it would load
an invalid sgl address in the ioctl path even if request length was zero.
Signed-off-by: NAdam Radford <aradford@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>
      53ca3535
    • V
      [SCSI] fcoe, libfc: adds enable/disable for fcoe interface · 55a66d3c
      由 Vasu Dev 提交于 
      This is to allow fcoemon util to enable or disable a fcoe interface
according to DCB link state change.

Adds sysfs module param enable and disable for this and also
updates existing other module param description to be consistent
and more accurate since older description had double "fcoe" word
with less meaningful netdev reference to user space.

Adds code to ignore redundant fc_lport_enter_reset handling for a
already disabled fcoe interface by checking LPORT_ST_DISABLED
or LPORT_ST_LOGO states, this also prevents lport state transition
on link flap on a disabled interface.

Above changes required lport state transition to get out of
disabled or logo state on call to fc_fabric_login.
Signed-off-by: NVasu Dev <vasu.dev@intel.com>
Signed-off-by: NRobert Love <robert.w.love@intel.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>
      55a66d3c
    • C
      [SCSI] libfc: reduce hold time on SCSI host lock · c1ecb90a
      由 Chris Leech 提交于 
      Introduce a new lock to protect the list of fc_fcp_pkt structs in libfc
instead of using the host lock.  This reduces the contention of this heavily
used lock, and I see up to a 25% performance gain in CPU bound small I/O
tests when scaling out across multiple quad-core CPUs.

The big win is in removing the host lock from the completion path
completely, as it does not need to be held around the call to scsi_done.
Signed-off-by: NChris Leech <christopher.leech@intel.com>
Signed-off-by: NRobert Love <robert.w.love@intel.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>
      c1ecb90a
    • A
      [SCSI] libfc: remote port gets stuck in restart state without really restarting · 5543c72e
      由 Abhijeet Joglekar 提交于 
      We ran into a scenario where a remote port goes into RESTART state, but
never gets added to scsi transport. The running vmcore showed the following:
a) Port was in RESTART state
b) rdata->event was STOP
c) no work gets scheduled for the remote work to fc_rport_work

After this point, shut/no-shut of the remote port did not cause the port
to get re-discovered. The port would move betwen DELETE and RESTART states,
but the event would always be STOP, no work would get scheduled to
fc_rport_work and the port would not get added to scsi_transport.

The problem is that rdata->event is not set to NONE after a port is
restarted. After this point, no more work gets scheduled for the remote port
since new work is scheduled only if rdata->event is non-NONE. So, the event
and state keep changing, but fc_rport_work does not get scheduled to actually
handle the event.

Here's a transition of states that explains the above observation:

) Port is first in READY State, event is NONE

2) RSCN on shut, port goes to DELETED, event is stop

3) Before fc_rport_work runs, RSCN on no-shut, port goes to RESTART, event is
still STOP

4) fc_rport_work gets scheduled, removes the port from transport, sees state
as RESTART, begins the PLOGI state machine, event remains as STOP (event NOT
changed to NONE, this is the bug)

5) Plogi state machine completes, port state goes to READY, event goes to
READY, but no work is scheduled since event was STOP (non-NONE) before.
Fc_rport_work is not scheduled, port remains in READY state, but is not added
to transport.

Things are broken at this point. Libfc rport is ready, but no transport rport
created.

6) now a shut causes port state to change to DELETE, event to change to STOP,
no work gets scheduled

7) no-shut causes port state to change to RESTART, event remains at STOP,
no work gets scheduled

(6) and (7) now get repeated everytime we do shut/no-shut. No way to get out
of this state. Fcc reset does not help too.

Only way to get out is to load/unload module.

Fix is to set rdata->event to NONE while processing the STOP/LOGO/FAILED
events, inside the discovery and rport locks.
Signed-off-by: NAbhijeet Joglekar <abjoglek@cisco.com>
Signed-off-by: NRobert Love <robert.w.love@intel.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>
      5543c72e
  9. 11 12月, 2009 8 次提交
  11. 10 12月, 2009 24 次提交