diff options
Diffstat (limited to 'fs/aio.c')
| -rw-r--r-- | fs/aio.c | 27 |
1 files changed, 20 insertions, 7 deletions
@@ -373,6 +373,14 @@ static int aio_migratepage(struct address_space *mapping, struct page *new, pgoff_t idx; int rc; + /* + * We cannot support the _NO_COPY case here, because copy needs to + * happen under the ctx->completion_lock. That does not work with the + * migration workflow of MIGRATE_SYNC_NO_COPY. + */ + if (mode == MIGRATE_SYNC_NO_COPY) + return -EINVAL; + rc = 0; /* mapping->private_lock here protects against the kioctx teardown. */ @@ -441,10 +449,9 @@ static const struct address_space_operations aio_ctx_aops = { #endif }; -static int aio_setup_ring(struct kioctx *ctx) +static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) { struct aio_ring *ring; - unsigned nr_events = ctx->max_reqs; struct mm_struct *mm = current->mm; unsigned long size, unused; int nr_pages; @@ -707,6 +714,12 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) int err = -ENOMEM; /* + * Store the original nr_events -- what userspace passed to io_setup(), + * for counting against the global limit -- before it changes. + */ + unsigned int max_reqs = nr_events; + + /* * We keep track of the number of available ringbuffer slots, to prevent * overflow (reqs_available), and we also use percpu counters for this. * @@ -724,14 +737,14 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) return ERR_PTR(-EINVAL); } - if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL)) + if (!nr_events || (unsigned long)max_reqs > aio_max_nr) return ERR_PTR(-EAGAIN); ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); if (!ctx) return ERR_PTR(-ENOMEM); - ctx->max_reqs = nr_events; + ctx->max_reqs = max_reqs; spin_lock_init(&ctx->ctx_lock); spin_lock_init(&ctx->completion_lock); @@ -753,7 +766,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) if (!ctx->cpu) goto err; - err = aio_setup_ring(ctx); + err = aio_setup_ring(ctx, nr_events); if (err < 0) goto err; @@ -764,8 +777,8 @@ static struct kioctx *ioctx_alloc(unsigned nr_events) /* limit the number of system wide aios */ spin_lock(&aio_nr_lock); - if (aio_nr + nr_events > (aio_max_nr * 2UL) || - aio_nr + nr_events < aio_nr) { + if (aio_nr + ctx->max_reqs > aio_max_nr || + aio_nr + ctx->max_reqs < aio_nr) { spin_unlock(&aio_nr_lock); err = -EAGAIN; goto err_ctx; |