cifs: fail i/o on soft mounts if sessionsetup errors out

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index 8ab1cf4..7187d03 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -40,6 +40,7 @@
 #include <linux/ramfs.h>
 #include <linux/percpu-refcount.h>
 #include <linux/mount.h>
+#include <linux/nospec.h>
 
 #include <asm/kmap_types.h>
 #include <asm/uaccess.h>
@@ -68,9 +69,9 @@ struct aio_ring {
 #define AIO_RING_PAGES 8
 
 struct kioctx_table {
-       struct rcu_head rcu;
-       unsigned        nr;
-       struct kioctx   *table[];
+       struct rcu_head         rcu;
+       unsigned                nr;
+       struct kioctx __rcu     *table[];
 };
 
 struct kioctx_cpu {
@@ -327,7 +328,7 @@ static int aio_ring_mremap(struct vm_area_struct *vma)
        for (i = 0; i < table->nr; i++) {
                struct kioctx *ctx;
 
-               ctx = table->table[i];
+               ctx = rcu_dereference(table->table[i]);
                if (ctx && ctx->aio_ring_file == file) {
                        if (!atomic_read(&ctx->dead)) {
                                ctx->user_id = ctx->mmap_base = vma->vm_start;
@@ -628,9 +629,8 @@ static void free_ioctx_users(struct percpu_ref *ref)
        while (!list_empty(&ctx->active_reqs)) {
                req = list_first_entry(&ctx->active_reqs,
                                       struct aio_kiocb, ki_list);
-
-               list_del_init(&req->ki_list);
                kiocb_cancel(req);
+               list_del_init(&req->ki_list);
        }
 
        spin_unlock_irq(&ctx->ctx_lock);
@@ -651,9 +651,9 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
        while (1) {
                if (table)
                        for (i = 0; i < table->nr; i++)
-                               if (!table->table[i]) {
+                               if (!rcu_access_pointer(table->table[i])) {
                                        ctx->id = i;
-                                       table->table[i] = ctx;
+                                       rcu_assign_pointer(table->table[i], ctx);
                                        spin_unlock(&mm->ioctx_lock);
 
                                        /* While kioctx setup is in progress,
@@ -828,8 +828,8 @@ static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
        }
 
        table = rcu_dereference_raw(mm->ioctx_table);
-       WARN_ON(ctx != table->table[ctx->id]);
-       table->table[ctx->id] = NULL;
+       WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
+       RCU_INIT_POINTER(table->table[ctx->id], NULL);
        spin_unlock(&mm->ioctx_lock);
 
        /* free_ioctx_reqs() will do the necessary RCU synchronization */
@@ -874,7 +874,8 @@ void exit_aio(struct mm_struct *mm)
 
        skipped = 0;
        for (i = 0; i < table->nr; ++i) {
-               struct kioctx *ctx = table->table[i];
+               struct kioctx *ctx =
+                       rcu_dereference_protected(table->table[i], true);
 
                if (!ctx) {
                        skipped++;
@@ -1063,10 +1064,11 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)
        if (!table || id >= table->nr)
                goto out;
 
-       ctx = table->table[id];
+       id = array_index_nospec(id, table->nr);
+       ctx = rcu_dereference(table->table[id]);
        if (ctx && ctx->user_id == ctx_id) {
-               percpu_ref_get(&ctx->users);
-               ret = ctx;
+               if (percpu_ref_tryget_live(&ctx->users))
+                       ret = ctx;
        }
 out:
        rcu_read_unlock();