Subject: spufs: Fix lost events in poll/epoll on mfc From: Kazunori Asayama When waiting for I/O events on mfc in an SPU context by using poll/epoll syscalls, some of the events can be lost because of wrong order of poll_wait and MFC status checks in the spufs_mfc_poll function and non-atomic update of tagwait. Here is a patch to fix the problem. Signed-off-by: Kazunori Asayama Signed-off-by: Arnd Bergmann --- arch/powerpc/platforms/cell/spufs/file.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) Index: linux-2.6/arch/powerpc/platforms/cell/spufs/file.c =================================================================== --- linux-2.6.orig/arch/powerpc/platforms/cell/spufs/file.c +++ linux-2.6/arch/powerpc/platforms/cell/spufs/file.c @@ -1499,14 +1499,15 @@ static ssize_t spufs_mfc_write(struct fi if (status) ret = status; } - spu_release(ctx); if (ret) - goto out; + goto out_unlock; ctx->tagwait |= 1 << cmd.tag; ret = size; +out_unlock: + spu_release(ctx); out: return ret; } @@ -1517,14 +1518,14 @@ static unsigned int spufs_mfc_poll(struc u32 free_elements, tagstatus; unsigned int mask; + poll_wait(file, &ctx->mfc_wq, wait); + spu_acquire(ctx); ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2); free_elements = ctx->ops->get_mfc_free_elements(ctx); tagstatus = ctx->ops->read_mfc_tagstatus(ctx); spu_release(ctx); - poll_wait(file, &ctx->mfc_wq, wait); - mask = 0; if (free_elements & 0xffff) mask |= POLLOUT | POLLWRNORM;