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Commit eff9cf8d authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Geert Uytterhoeven
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[SCSI] atari_scsi: Fix sleep_on race 



sleep_on is known broken and going away. The atari_scsi driver is one of
two remaining users in the falcon_get_lock() function, which is a rather
crazy piece of code. This does not attempt to fix the driver's locking
scheme in general, but at least prevents falcon_get_lock from going to
sleep when no other thread holds the same lock or tries to get it,
and we no longer schedule with irqs disabled.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
[MSch: fixed completion conditions missed in Arnds' original RFC patch]
Signed-off-by: default avatarMichael Schmitz <schmitz@debian.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: James E.J. Bottomley <JBottomley@parallels.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent ecc79d49

drivers/scsi/atari_scsi.c

+9 −3
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ 
#include <linux/init.h>

#include <linux/nvram.h>

#include <linux/bitops.h>

#include <linux/wait.h>



#include <asm/setup.h>

#include <asm/atarihw.h>
@@ -549,8 +550,10 @@ static void falcon_get_lock(void) 


	local_irq_save(flags);



	while (!in_irq() && falcon_got_lock && stdma_others_waiting())

		sleep_on(&falcon_fairness_wait);

	wait_event_cmd(falcon_fairness_wait,

		in_interrupt() || !falcon_got_lock || !stdma_others_waiting(),

		local_irq_restore(flags),

		local_irq_save(flags));



	while (!falcon_got_lock) {

		if (in_irq())
@@ -562,7 +565,10 @@ static void falcon_get_lock(void) 
			falcon_trying_lock = 0;

			wake_up(&falcon_try_wait);

		} else {

			sleep_on(&falcon_try_wait);

			wait_event_cmd(falcon_try_wait,

				falcon_got_lock && !falcon_trying_lock,

				local_irq_restore(flags),

				local_irq_save(flags));

		}

	}