alpha: simplify TIF_NEED_RESCHED handling (7721d3c2) · Commits · 戴 / test

In case we have both NEED_RESCHED and SIGPENDING/NOTIFY_RESUME, handle the latter first. We'll get to original priorities in the next commit, but now that allows to simplify the treatment of NEED_RESCHED-only case nicely. Namely, now there no need to preserve the data for restarts across the call of schedule() in $work_resched; we can get there only if we had either returned from syscall without SIGPENDING (in which case we should've had no restart-worthy return value and want no restarts) or already got through do_notify_resume() call (in which case we want no restarts anymore). So we can just slap 0 into $19 instead of preserving it (and $20). Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

arch/alpha/kernel/entry.S

+9 −17

Original line number	Diff line number	Diff line
		@@ -372,26 +372,18 @@ $ret_success:
		.align 4
		.ent work_pending
		work_pending:
		and $5, _TIF_NEED_RESCHED, $2
		beq $2, $work_notifysig
		and $5, _TIF_NOTIFY_RESUME \| _TIF_SIGPENDING, $2
		bne $2, $work_notifysig

		$work_resched:
		subq $sp, 16, $sp
		stq $19, 0($sp) /* save syscall nr */
		stq $20, 8($sp) /* and error indication (a3) */
		/*
		* We can get here only if we returned from syscall without SIGPENDING
		* or got through work_notifysig already. Either case means no syscall
		* restarts for us, so let $19 and $20 burn.
		*/
		jsr $26, schedule
		ldq $19, 0($sp)
		ldq $20, 8($sp)
		addq $sp, 16, $sp
		/* Make sure need_resched and sigpending don't change between
		sampling and the rti. */
		lda $16, 7
		call_pal PAL_swpipl
		ldl $5, TI_FLAGS($8)
		and $5, _TIF_WORK_MASK, $2
		beq $2, restore_all
		and $5, _TIF_NEED_RESCHED, $2
		bne $2, $work_resched
		mov 0, $19
		br ret_to_user

		$work_notifysig:
		mov $sp, $16

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