James Smart 5115854bb3 scsi: lpfc: Correct race with abort on completion path
[ Upstream commit ca7fb76e091f889cfda1287c07a9358f73832b39 ]

On io completion, the driver is taking an adapter wide lock and nulling the
scsi command back pointer.  The nulling of the back pointer is to signify the
io was completed and the scsi_done() routine was called.  However, the routine
makes no check to see if the abort routine had done the same thing and
possibly nulled the pointer. Thus it may doubly-complete the io.

Make the following mods:

- Check to make sure forward progress (call scsi_done()) only happens if the
  command pointer was non-null.

- As the taking of the lock, which is adapter wide, is very costly on a system
  under load, null the pointer using an xchg operation rather than under lock.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-13 11:15:00 -08:00
2018-11-13 11:14:53 -08:00
2018-09-26 08:38:04 +02:00
2018-11-10 07:48:36 -08:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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