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* [PATCH 0/4] Modify bitmap_set_value() to suppress compiler warning
@ 2020-11-20 17:42 Syed Nayyar Waris
  2020-11-20 17:44 ` [PATCH 1/4] bitmap: Modify bitmap_set_value() to check bitmap length Syed Nayyar Waris
                   ` (3 more replies)
  0 siblings, 4 replies; 13+ messages in thread
From: Syed Nayyar Waris @ 2020-11-20 17:42 UTC (permalink / raw)
  To: akpm
  Cc: andriy.shevchenko, vilhelm.gray, michal.simek, arnd, rrichter,
	linus.walleij, bgolaszewski, yamada.masahiro, rui.zhang,
	daniel.lezcano, amit.kucheria, linux-arch, linux-gpio,
	linux-kernel, linux-arm-kernel, linux-pm

Hi All,

The purpose of this patchset is to suppress the compiler warning (-Wtype-limits).

In function bitmap_set_value(), add explicit check to see if the value being
written into the bitmap does not fall outside the bitmap.
The situation that it is falling outside is never possible in the code 
because the boundaries are required to be correct before the function is 
called. The responsibility is on the caller for ensuring the boundaries 
are correct.
The code change is simply to silence the GCC warning messages
because GCC is not aware that the boundaries have already been checked.
As such, we're better off using __builtin_unreachable() here because we
can avoid the latency of the conditional check entirely.

Michal,
What do you think of [PATCH 4/4]? Is the conditional check needed, and also whether
returning -EINVAL looks good?

Syed Nayyar Waris (4):
  bitmap: Modify bitmap_set_value() to check bitmap length
  lib/test_bitmap.c: Modify for_each_set_clump test
  gpio: xilinx: Modify bitmap_set_value() calls
  gpio: xilinx: Add extra check if sum of widths exceed 64

 drivers/gpio/gpio-xilinx.c | 18 ++++++++++++------
 include/linux/bitmap.h     | 35 +++++++++++++++++++++--------------
 lib/test_bitmap.c          |  4 ++--
 3 files changed, 35 insertions(+), 22 deletions(-)


base-commit: b640c4e12bbe1f0b6383c3ef788a89e5427c763f
-- 
2.29.0


^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2020-12-12 10:12 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-20 17:42 [PATCH 0/4] Modify bitmap_set_value() to suppress compiler warning Syed Nayyar Waris
2020-11-20 17:44 ` [PATCH 1/4] bitmap: Modify bitmap_set_value() to check bitmap length Syed Nayyar Waris
2020-11-20 17:59   ` William Breathitt Gray
2020-11-20 18:02     ` Syed Nayyar Waris
2020-11-20 18:43   ` [RESEND PATCH " Syed Nayyar Waris
2020-11-20 17:45 ` [PATCH 2/4] lib/test_bitmap.c: Modify for_each_set_clump test Syed Nayyar Waris
2020-11-20 18:44   ` [RESEND PATCH " Syed Nayyar Waris
2020-11-20 17:46 ` [PATCH 3/4] gpio: xilinx: Modify bitmap_set_value() calls Syed Nayyar Waris
2020-11-20 18:45   ` [RESEND PATCH " Syed Nayyar Waris
2020-12-01 15:33   ` Bartosz Golaszewski
2020-12-12  9:39     ` Syed Nayyar Waris
2020-11-20 17:48 ` [PATCH 4/4] gpio: xilinx: Add extra check to see if sum of widths exceed 64 Syed Nayyar Waris
2020-11-20 18:46   ` [RESEND PATCH 4/4] gpio: xilinx: Add extra check " Syed Nayyar Waris

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