search for: smp_mb__after_atomic

The vhost_scsi.ko code used several atomic variables at one point. Later they were dropped or converted to regular ints protected by a mutex. The commit that made these changes left an unused smp_mb__after_atomic() in vhost_scsi_set_endpoint(). It was previously used after incrementing vhost_scsi->vhost_ref_cnt but this field has been dropped: - atomic_inc(&vs->vhost_ref_cnt); smp_mb__after_atomic_inc(); Reported-by: Andrea Parri <andrea.parri at amarulasolutions.com> Fixes:...

The vhost_scsi.ko code used several atomic variables at one point. Later they were dropped or converted to regular ints protected by a mutex. The commit that made these changes left an unused smp_mb__after_atomic() in vhost_scsi_set_endpoint(). It was previously used after incrementing vhost_scsi->vhost_ref_cnt but this field has been dropped: - atomic_inc(&vs->vhost_ref_cnt); smp_mb__after_atomic_inc(); Reported-by: Andrea Parri <andrea.parri at amarulasolutions.com> Fixes:...

On 2019/4/16 ??6:47, Stefan Hajnoczi wrote: > The vhost_scsi.ko code used several atomic variables at one point. > Later they were dropped or converted to regular ints protected by a > mutex. > > The commit that made these changes left an unused smp_mb__after_atomic() > in vhost_scsi_set_endpoint(). It was previously used after incrementing > vhost_scsi->vhost_ref_cnt but this field has been dropped: > > - atomic_inc(&vs->vhost_ref_cnt); > smp_mb__after_atomic_inc(); > > Reported-by: Andrea Parri <andrea.parri...

On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote: > On s390 read_barrier_depends, smp_read_barrier_depends > smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the > asm-generic variants exactly. Drop the local definitions and pull in > asm-generic/barrier.h instead. > > This is in preparation to refactoring this code area. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > Acked-by: Arnd Bergmann <arnd at ar...

On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote: > On s390 read_barrier_depends, smp_read_barrier_depends > smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the > asm-generic variants exactly. Drop the local definitions and pull in > asm-generic/barrier.h instead. > > This is in preparation to refactoring this code area. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > Acked-by: Arnd Bergmann <arnd at ar...

...CE(lock->tickets.head) == want) { >> + head = READ_ONCE(lock->tickets.head); >> + if (__tickets_equal(head, want)) { >> add_stats(TAKEN_SLOW_PICKUP, 1); >> goto out; > > This is off-topic, but with or without this change perhaps it makes sense > to add smp_mb__after_atomic(). It is nop on x86, just to make this code > more understandable for those (for me ;) who can never remember even the > x86 rules. > Hope you meant it for add_stat. yes smp_mb__after_atomic() would be harmless barrier() in x86. Did not add this V5 as yoiu though but this made me look a...

...CE(lock->tickets.head) == want) { >> + head = READ_ONCE(lock->tickets.head); >> + if (__tickets_equal(head, want)) { >> add_stats(TAKEN_SLOW_PICKUP, 1); >> goto out; > > This is off-topic, but with or without this change perhaps it makes sense > to add smp_mb__after_atomic(). It is nop on x86, just to make this code > more understandable for those (for me ;) who can never remember even the > x86 rules. > Hope you meant it for add_stat. yes smp_mb__after_atomic() would be harmless barrier() in x86. Did not add this V5 as yoiu though but this made me look a...

...on, 4 Jan 2016 14:20:42 +0100 > Peter Zijlstra <peterz at infradead.org> wrote: > > > On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote: > > > On s390 read_barrier_depends, smp_read_barrier_depends > > > smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the > > > asm-generic variants exactly. Drop the local definitions and pull in > > > asm-generic/barrier.h instead. > > > > > > This is in preparation to refactoring this code area. > > > > > > Signed-off-by: Michael S. Tsirkin <mst a...

...on, 4 Jan 2016 14:20:42 +0100 > Peter Zijlstra <peterz at infradead.org> wrote: > > > On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote: > > > On s390 read_barrier_depends, smp_read_barrier_depends > > > smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the > > > asm-generic variants exactly. Drop the local definitions and pull in > > > asm-generic/barrier.h instead. > > > > > > This is in preparation to refactoring this code area. > > > > > > Signed-off-by: Michael S. Tsirkin <mst a...

Changes since v1: - replaced my asm-generic patch with an equivalent patch already in tip - add wrappers with virt_ prefix for better code annotation, as suggested by David Miller - dropped XXX in patch names as this makes vger choke, Cc all relevant mailing lists on all patches (not personal email, as the list becomes too long then) I parked this in vhost tree for now, but the

Changes since v1: - replaced my asm-generic patch with an equivalent patch already in tip - add wrappers with virt_ prefix for better code annotation, as suggested by David Miller - dropped XXX in patch names as this makes vger choke, Cc all relevant mailing lists on all patches (not personal email, as the list becomes too long then) I parked this in vhost tree for now, but the

This is really trying to cleanup some virt code, as suggested by Peter, who said > You could of course go fix that instead of mutilating things into > sort-of functional state. This work is needed for virtio, so it's probably easiest to merge it through my tree - is this fine by everyone? Arnd, if you agree, could you ack this please? Note to arch maintainers: please don't

This is really trying to cleanup some virt code, as suggested by Peter, who said > You could of course go fix that instead of mutilating things into > sort-of functional state. This work is needed for virtio, so it's probably easiest to merge it through my tree - is this fine by everyone? Arnd, if you agree, could you ack this please? Note to arch maintainers: please don't

Changes since v2: - extended checkpatch tests for barriers, and added patches teaching it to warn about incorrect usage of barriers (__smp_xxx barriers are for use by asm-generic code only), should help prevent misuse by arch code to address comments by Russell King - patched more instances of xen to use virt_ barriers as suggested by Stefano Stabellini - implemented a 2 byte xchg on sh

Changes since v2: - extended checkpatch tests for barriers, and added patches teaching it to warn about incorrect usage of barriers (__smp_xxx barriers are for use by asm-generic code only), should help prevent misuse by arch code to address comments by Russell King - patched more instances of xen to use virt_ barriers as suggested by Stefano Stabellini - implemented a 2 byte xchg on sh

On Mon, Jan 04, 2016 at 02:54:20PM +0100, Peter Zijlstra wrote: > On Mon, Jan 04, 2016 at 02:36:58PM +0100, Peter Zijlstra wrote: > > On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote: > > > On Sat, Jan 02, 2016 at 11:24:38AM +0000, Russell King - ARM Linux wrote: > > > > > > My only concern is that it gives people an additional handle onto a

On Mon, Jan 04, 2016 at 02:54:20PM +0100, Peter Zijlstra wrote: > On Mon, Jan 04, 2016 at 02:36:58PM +0100, Peter Zijlstra wrote: > > On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote: > > > On Sat, Jan 02, 2016 at 11:24:38AM +0000, Russell King - ARM Linux wrote: > > > > > > My only concern is that it gives people an additional handle onto a

Hi, We have couple of places which can result in deadlock. This patch series fixes these. We can be called with fc->bg_lock (for background requests) while submitting a request. This leads to two constraints. - We can't end requests in submitter's context and call fuse_end_request() as it tries to take fc->bg_lock as well. So queue these requests on a list and use a worker to

On arm smp_store_mb, read_barrier_depends, smp_read_barrier_depends, smp_store_release, smp_load_acquire, smp_mb__before_atomic and smp_mb__after_atomic match the asm-generic variants exactly. Drop the local definitions and pull in asm-generic/barrier.h instead. This is in preparation to refactoring this code area. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Acked-by: Arnd Bergmann <arnd at arndb.de> --- arch/arm/include/as...

On s390 read_barrier_depends, smp_read_barrier_depends smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the asm-generic variants exactly. Drop the local definitions and pull in asm-generic/barrier.h instead. This is in preparation to refactoring this code area. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Acked-by: Arnd Bergmann <arnd at arndb.de> --- arch/s390/include/a...