For the little-endian SH771x kernels the driver has to byte-swap the RX/TX
buffers,  however yet unset physcial address from the TX descriptor is used
to call sh_eth_soft_swap(). Use 'skb->data' instead...

Fixes: 31fcb99d ("net: sh_eth: remove __flush_purge_region")
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 3365711d ("sh_eth: WARN on access to a register not implemented in
in  a particular chip") added WARN_ON() to sh_eth_{read|write}(), thus making
it  unacceptable for these functions to be *inline* anymore. Remove *inline*
and move the functions from the header to the driver itself. Below   is our
code economy with ARM gcc 4.7.3:

$ size drivers/net/ethernet/renesas/sh_eth.o{~,}
   text	   data	    bss	    dec	    hex	filename
  32489	   1140	      0	  33629	   835d	drivers/net/ethernet/renesas/sh_eth.o~
  25413	   1140	      0	  26553	   67b9	drivers/net/ethernet/renesas/sh_eth.o
Suggested-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In a low memory situation the following kernel oops occurs:

Unable to handle kernel NULL pointer dereference at virtual address 00000050
pgd = 8490c000
[00000050] *pgd=4651e831, *pte=00000000, *ppte=00000000
Internal error: Oops: 17 [#1] PREEMPT ARM
Modules linked in:
CPU: 0    Not tainted  (3.4-at16 #9)
PC is at skb_put+0x10/0x98
LR is at sh_eth_poll+0x2c8/0xa10
pc : [<8035f780>]    lr : [<8028bf50>]    psr: 60000113
sp : 84eb1a90  ip : 84eb1ac8  fp : 84eb1ac4
r10: 0000003f  r9 : 000005ea  r8 : 00000000
r7 : 00000000  r6 : 940453b0  r5 : 00030000  r4 : 9381b180
r3 : 00000000  r2 : 00000000  r1 : 000005ea  r0 : 00000000
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 10c53c7d  Table: 4248c059  DAC: 00000015
Process klogd (pid: 2046, stack limit = 0x84eb02e8)
[...]

This is  because netdev_alloc_skb() fails and 'mdp->rx_skbuff[entry]' is left
NULL but sh_eth_rx() later  uses it without checking.  Add such check...
Reported-by: NYasushi SHOJI <yashi@atmark-techno.com>
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While the ring allocation is done by a single function, sh_eth_ring_init(),
the ring deallocation was split into two functions (almost always called
one after the other) for no good reason. Merge  sh_eth_free_dma_buffer()
into sh_eth_ring_free() which allows us  to save space not only on the
direct calls  of the former function but also on the sh_eth_ring_init()'s
simplified error path...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The 'ret' local variable in sh_eth_ring_init() serves no useful purpose as
the only  values it gets assigned are 0 and -ENOMEM both of which could be
returned directly...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit  7d7355f5 ("sh_eth: Ensure proper ordering of descriptor active
bit write/read") did the right thing  but used too "heavy" barriers while
there were already "lighter" DMA barriers exactly  for this case...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The correct name of the RX descriptor 0 bit 30 is RDLE (receive descriptor
list end),  not  RDEL.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Iff the first dma_alloc_coherent()  call fails in sh_eth_ring_init(), the
following  is printed to the kernel console:

WARNING: CPU: 0 PID: 1 at drivers/base/dma-mapping.c:334 dma_common_free_remap+0x48/0x6c()
trying to free invalid coherent area:   (null)
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.3.0-rc7-dirty #969
Hardware name: Generic R8A7791 (Flattened Device Tree)
Backtrace:
[<c0013820>] (dump_backtrace) from [<c00139bc>] (show_stack+0x18/0x1c)
 r6:c0662856 r5:00000009 r4:00000000 r3:00204140
[<c00139a4>] (show_stack) from [<c0227510>] (dump_stack+0x74/0x90)
[<c022749c>] (dump_stack) from [<c0026ef4>] (warn_slowpath_common+0x8c/0xb8)
 r4:ee84dce0 r3:c0712774
[<c0026e68>] (warn_slowpath_common) from [<c0026fc4>] (warn_slowpath_fmt+0x38/0x40)
 r8:ee7f8000 r7:c0734520 r6:00001000 r5:20000008 r4:00000000
[<c0026f90>] (warn_slowpath_fmt) from [<c02df404>] (dma_common_free_remap+0x48/0x6c)
 r3:00000000 r2:c0662871
[<c02df3bc>] (dma_common_free_remap) from [<c001b9fc>] (__arm_dma_free+0xb8/0xd4)
r6:00000001 r5:00000000 r4:00001000 r3:ee8c5584
[<c001b944>] (__arm_dma_free) from [<c001ba68>] (arm_dma_free+0x24/0x2c)
 r10:0000016b r8:00000000 r7:ee9bc830 r6:00000000 r5:00000400 r4:ee9bc800
[<c001ba44>] (arm_dma_free) from [<c032ebf0>] (sh_eth_ring_init+0x110/0x138)
[<c032eae0>] (sh_eth_ring_init) from [<c033179c>] (sh_eth_open+0x94/0x1f4)
 r6:00000000 r5:ee9bcd18 r4:ee9bc800
[<c0331708>] (sh_eth_open) from [<c041bf7c>] (__dev_open+0x84/0x104)
 r6:c0565c50 r5:00000000 r4:ee9bc800
[<c041bef8>] (__dev_open) from [<c041c208>] (__dev_change_flags+0x94/0x13c)
 r7:00001002 r6:00000001 r5:00001003 r4:ee9bc800
[<c041c174>] (__dev_change_flags) from [<c041c2e8>] (dev_change_flags+0x20/0x50)
 r7:c072c8a0 r6:00000138 r5:00001002 r4:ee9bc800
[<c041c2c8>] (dev_change_flags) from [<c06e8d4c>] (ip_auto_config+0x174/0xf7c)
 r8:00001002 r7:c072c8a0 r6:c0700040 r5:00000001 r4:ee9bc800 r3:00000101
[<c06e8bd8>] (ip_auto_config) from [<c000a810>] (do_one_initcall+0x100/0x1c8)
 r10:c06f883c r9:00000000 r8:c06e8bd8 r7:c0734000 r6:c070e918 r5:c070e918
 r4:ee083640
[<c000a710>] (do_one_initcall) from [<c06c9ddc>] (kernel_init_freeable+0x11c/0x1ec)
 r10:c06f883c r9:00000000 r8:00000099 r7:c0734000 r6:c070372c r5:c06f8834
 r4:00000007
[<c06c9cc0>] (kernel_init_freeable) from [<c0514d78>] (kernel_init+0x14/0xec)
 r10:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c0514d64 r4:c0734000
[<c0514d64>] (kernel_init) from [<c0010458>] (ret_from_fork+0x14/0x3c)
 r4:00000000 r3:ee84c000

This is because the code jumps to a wrong label and so tries to free yet
unallocated coherent memory.  Fix the *goto* in question.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sh_eth_ring_free()  called in the sh_eth_ring_init()'s error path expects
the arrays pointed  to  by 'sh_eth_private::[rt]x_skbuff' to be initialized
with NULLs but they are allocated with just kmalloc_array() and so are left
filled with random data. Use kcalloc() instead.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The RX buffer size calulation failed to account for the length granularity
(which is now 32 bytes)...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Both  Renesas R-Car and RZ/A1 manuals state that RX buffer  length must be
a multiple of 32 bytes, while the driver  only uses 16 byte granularity...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The driver overrides the error returned by platform_get_irq() with -ENODEV
which e.g. precludes the deferred  probing from working. Propagate the real
error code to the driver core instead.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The statistics registers have write-clear behaviour, which means we
will lose any increment between the read and write.  Mitigate this by
only clearing when we read a non-zero value, so we will never falsely
report a total of zero.  This also saves time as we only handle
error statistics here and they won't often be incremented.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are many different sets of registers implemented by the
different versions of this controller, and we can only expect this to
get more complicated in future.  Limit how much ethtool needs to know
by including an explicit bitmap of which registers are included in the
dump, allowing room for future growth in the number of possible
registers.

As I don't have datasheets for all of these, I've only included
registers that are:

- defined in all 5 register type arrays, or
- used by the driver, or
- documented in the datasheet I have

Add one new capability flag so we can tell whether the RTRATE
register is implemented.

Delete the TSU_ADRL0 and TSU_ADR{H,L}31 definitions, as they weren't
used and the address table is already assumed to be contiguous.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently we may silently read/write a register at offset 0.  Change
this to WARN and then ignore the write or read-back all-ones.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Acked-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

At least on the R8A7790, RFS8 reflects the RINT8 (multicast) MAC
status flag.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

My previous fix to clear padding of short frames used skb->len as the
DMA length, assuming that skb_padto() extended skb->len to include the
padding.  That isn't the case; we need to use skb_put_padto() instead.

(This wasn't immediately obvious because software padding isn't
actually needed on the R-Car H2.  We could make it conditional on
which chip is being driven, but it's probably not worth the effort.)
Reported-by: N"Violeta Menéndez González" <violeta.menendez@codethink.co.uk>
Fixes: 612a17a54b50 ("sh_eth: Fix padding of short frames on TX")
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit fd9af07c.

The hardware manual states that the frame error and multicast bits are
copied to bits 9:0 of RD0, not bits 25:16.  I've tested that this is
true for RFS1 (CRC error), RFS3 (frame too short), RFS4 (frame too
long) and RFS8 (multicast).

Also adjust a comment to agree with this.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of RX ring underrun (RDE), we attempt to reset the software
descriptor pointers (dirty_rx and cur_rx) to match where the hardware
will read the next descriptor from, as that might not be the first
dirty descriptor.  This relies on reading RDFAR, but that register
doesn't exist on all supported chips - specifically, not on the R-Car
chips.  This will result in unpredictable behaviour on those chips
after an RDE.

Make this pointer reset conditional and assume that it isn't needed on
the R-Car chips.  This fix also assumes that RDFAR is never exposed at
offset 0 in the memory map - this is currently true, and a subsequent
commit will fix the ambiguity between offset 0 and no-offset in the
register offset maps.

Fixes: 79fba9f5 ("net: sh_eth: fix the rxdesc pointer when rx ...")
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When submitting a DMA descriptor, the active bit must be written last.
When reading a completed DMA descriptor, the active bit must be read
first.

Add memory barriers to ensure that this ordering is maintained.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 740c7f31 ("sh_eth: Ensure DMA engines are stopped before
freeing buffers") added a call to sh_eth_reset() to the
sh_eth_set_ringparam() and sh_eth_close() paths.

However, setting the software reset bit(s) in the EDMR register resets
the MAC Address Registers to zero. Hence after kexec, the new kernel
doesn't detect a valid MAC address and assigns a random MAC address,
breaking DHCP.

Set the MAC address again after the reset in sh_eth_dev_exit() to fix
this.

Tested on r8a7740/armadillo (GETHER) and r8a7791/koelsch (FAST_RCAR).

Fixes: 740c7f31 ("sh_eth: Ensure DMA engines are stopped before freeing buffers")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Use the return value of dma_map_single(), rather than calling
  virt_to_page() separately
- Check for mapping failue
- Call dma_unmap_single() rather than dma_sync_single_for_cpu()
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

dma_map_single() may fail if an IOMMU or swiotlb is in use, so
we need to check for this.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently we try to clear EDRRR and EDTRR and immediately continue to
free buffers.  This is unsafe because:

- In general, register writes are not serialised with DMA, so we still
  have to wait for DMA to complete somehow
- The R8A7790 (R-Car H2) manual states that the TX running flag cannot
  be cleared by writing to EDTRR
- The same manual states that clearing the RX running flag only stops
  RX DMA at the next packet boundary

I applied this patch to the driver to detect DMA writes to freed
buffers:

> --- a/drivers/net/ethernet/renesas/sh_eth.c
> +++ b/drivers/net/ethernet/renesas/sh_eth.c
> @@ -1098,7 +1098,14 @@ static void sh_eth_ring_free(struct net_device *ndev)
>  	/* Free Rx skb ringbuffer */
>  	if (mdp->rx_skbuff) {
>  		for (i = 0; i < mdp->num_rx_ring; i++)
> +			memcpy(mdp->rx_skbuff[i]->data,
> +			       "Hello, world", 12);
> +		msleep(100);
> +		for (i = 0; i < mdp->num_rx_ring; i++) {
> +			WARN_ON(memcmp(mdp->rx_skbuff[i]->data,
> +				       "Hello, world", 12));
>  			dev_kfree_skb(mdp->rx_skbuff[i]);
> +		}
>  	}
>  	kfree(mdp->rx_skbuff);
>  	mdp->rx_skbuff = NULL;

then ran the loop:

    while ethtool -G eth0 rx 128 ; ethtool -G eth0 rx 64; do echo -n .; done

and 'ping -f' toward the sh_eth port from another machine.  The
warning fired several times a minute.

To fix these issues:

- Deactivate all TX descriptors rather than writing to EDTRR
- As there seems to be no way of telling when RX DMA is stopped,
  perform a soft reset to ensure that both DMA enginess are stopped
- To reduce the possibility of the reset truncating a transmitted
  frame, disable egress and wait a reasonable time to reach a
  packet boundary before resetting
- Update statistics before resetting

(The 'reasonable time' does not allow for CS/CD in half-duplex
mode, but half-duplex no longer seems reasonable!)
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If RX traffic is overflowing the FIFO or DMA ring, logging every time
this happens just makes things worse.  These errors are visible in the
statistics anyway.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to stop the RX path accessing the RX ring while it's being
stopped or resized, we clear the interrupt mask (EESIPR) and then call
free_irq() or synchronise_irq().  This is insufficient because the
interrupt handler or NAPI poller may set EESIPR again after we clear
it.  Also, in sh_eth_set_ringparam() we currently don't disable NAPI
polling at all.

I could easily trigger a crash by running the loop:

   while ethtool -G eth0 rx 128 && ethtool -G eth0 rx 64; do echo -n .; done

and 'ping -f' toward the sh_eth port from another machine.

To fix this:
- Add a software flag (irq_enabled) to signal whether interrupts
  should be enabled
- In the interrupt handler, if the flag is clear then clear EESIPR
  and return
- In the NAPI poller, if the flag is clear then don't set EESIPR
- Set the flag before enabling interrupts in sh_eth_dev_init() and
  sh_eth_set_ringparam()
- Clear the flag and serialise with the interrupt and NAPI
  handlers before clearing EESIPR in sh_eth_close() and
  sh_eth_set_ringparam()

After this, I could run the loop for 100,000 iterations successfully.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the device is down then no packet buffers should be allocated.
We also must not touch its registers as it may be powered off.
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We must only ever stop TX queues when they are full or the net device
is not 'ready' so far as the net core, and specifically the watchdog,
is concerned.  Otherwise, the watchdog may fire *immediately* if no
packets have been added to the queue in the last 5 seconds.

What's more, sh_eth_tx_timeout() will likely crash if called while
we're resizing the TX ring.

I could easily trigger this by running the loop:

   while ethtool -G eth0 rx 128 && ethtool -G eth0 rx 64; do echo -n .; done
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If an skb to be transmitted is shorter than the minimum Ethernet frame
length, we currently set the DMA descriptor length to the minimum but
do not add zero-padding.  This could result in leaking sensitive
data.  We also pass different lengths to dma_map_single() and
dma_unmap_single().

Use skb_padto() to pad properly, before calling dma_map_single().
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add sh_eth_{suspend|resume}() implementing {suspend|resume|freeze|thaw|poweroff|
restore}() PM methods to make it possible to restore from hibernation not only
in Linux  but also in e.g. U-Boot and  to have more determined state on resume/
restore.
Signed-off-by: NMikhail Ulyanov <mikhail.ulyanov@cogentembedded.com>
[Sergei: moved sh_eth_{suspend|resume}() before sh_eth_runtime_nop(), enclosed
them with #ifdef CONFIG_PM_SLEEP, reordered the local variables, got rid of
*goto* and label, reordered macro invocations, renamed, modified the changelog.]
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use SET_RUNTIME_PM_OPS() macro to initialize the runtime PM method pointers in
the 'struct dev_pm_ops'.
Signed-off-by: NMikhail Ulyanov <mikhail.ulyanov@cogentembedded.com>
[Sergei: renamed, added the changelog.]
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The driver connects and disconnects the PHY device whenever the
net device is brought up and down.  The ethtool get_settings,
set_settings and nway_reset operations will dereference a null
or dangling pointer if called while it is down.

I think it would be preferable to keep the PHY connected, but there
may be good reasons not to.

As an immediate fix for this bug:
- Set the phydev pointer to NULL after disconnecting the PHY
- Change those three operations to return -ENODEV while the PHY is
  not connected
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently net_device_ops::set_rx_mode is only implemented for
chips with a TSU (multiple address table).  However we do need
to turn the PRM (promiscuous) flag on and off for other chips.

- Remove the unlikely() from the TSU functions that we may safely
  call for chips without a TSU
- Make setting of the MCT flag conditional on the tsu capability flag
- Rename sh_eth_set_multicast_list() to sh_eth_set_rx_mode() and plumb
  it into both net_device_ops structures
- Remove the previously-unreachable branch in sh_eth_rx_mode() that
  would otherwise reset the flags to defaults for non-TSU chips
Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace "unsigned long" by "u32" when handling 32-bit register data.

A.o., this saves 11 * 36 bytes in the static sh_eth_cpu_data structures
when compiling for 64-bit.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit b284fbe3 ("sh_eth: Fix access to TRSCER register") wanted
to add a .trscer_err_mask value to the R-Car Gen2 family-specific data
structure (r8a779x_data), but it was accidentally added to the
SH7724-specific data structure (sh7724_data).

Presumably this happened due to a patch conflict with commit
d407bc02 ("sh-eth: Set fdr_value of R-Car SoCs"), which added
another field at the same position.

Move the field setting to fix this.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Fixes: b284fbe3 ("sh_eth: Fix access to TRSCER register")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TRSCER register is configured differently by SoCs. TRSCER of R-Car Gen2 is
RINT8 bit only valid, other bits are reserved bits. This removes access to
TRSCER register reserve bit by adding variable trscer_err_mask to
sh_eth_cpu_data structure, set the register information to each SoCs.
Signed-off-by: NNobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

FDR register of R-Car set in fdr_value can have the original settings.
This sets the value that is suitable for each SoCs to fdr_value of R8A777x
and R8A779x.
Signed-off-by: NNobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

PTR_ALIGN macro after skb_reserve is redundant, because skb_reserve
function adjusts the alignment of skb->data.
Signed-off-by: NMitsuhiro Kimura <mitsuhiro.kimura.kc@renesas.com>
Signed-off-by: NYoshihiro Kaneko <ykaneko0929@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Both of 'boguscnt' and 'quota' have nearly meaning as the condition of
the reception loop.
In order to cut down redundant processing, this patch changes excess
judgement.
Signed-off-by: NMitsuhiro Kimura <mitsuhiro.kimura.kc@renesas.com>
Signed-off-by: NYoshihiro Kaneko <ykaneko0929@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>