tree 85776a4c9b1602646405fd7f5f4c336824b2b0f6
parent 82e54a6aaf8aec971fb16afa3a4404e238a1b98b
author Martin Michlmayr <tbm@cyrius.com> 1349395885 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1349460277 +0900

drivers/scsi/atp870u.c: fix bad use of udelay

The ACARD driver calls udelay() with a value > 2000, which leads to to
the following compilation error on ARM:

  ERROR: "__bad_udelay" [drivers/scsi/atp870u.ko] undefined!
  make[1]: *** [__modpost] Error 1

This is because udelay is defined on ARM, roughly speaking, as

	#define udelay(n) ((n) > 2000 ? __bad_udelay() : \
		__const_udelay((n) * ((2199023U*HZ)>>11)))

The argument to __const_udelay is the number of jiffies to wait divided
by 4, but this does not work unless the multiplication does not
overflow, and that is what the build error is designed to prevent.  The
intended behavior can be achieved by using mdelay to call udelay
multiple times in a loop.

[jrnieder@gmail.com: adding context]
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>