kfifo: fix warn_unused_result

Fix the "ignoring return value of '...', declared with attribute
warn_unused_result" compiler warning in several users of the new kfifo
API.

It removes the __must_check attribute from kfifo_in() and
kfifo_in_locked() which must not necessary performed.

Fix the allocation bug in the nozomi driver file, by moving out the
kfifo_alloc from the interrupt handler into the probe function.

Fix the kfifo_out() and kfifo_out_locked() users to handle a unexpected
end of fifo.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 51 insertions, 16 deletions

diff --git a/drivers/char/nozomi.c b/drivers/char/nozomi.c
index 9ef243429014..7d73cd430340 100644
--- a/drivers/char/nozomi.c
+++ b/drivers/char/nozomi.c
@@ -685,8 +685,6 @@ static int nozomi_read_config_table(struct nozomi *dc)
                 dump_table(dc);
 
                 for (i = PORT_MDM; i < MAX_PORT; i++) {
-                        kfifo_alloc(&dc->port[i].fifo_ul,
-                                FIFO_BUFFER_SIZE_UL, GFP_ATOMIC);
                         memset(&dc->port[i].ctrl_dl, 0, sizeof(struct ctrl_dl));
                         memset(&dc->port[i].ctrl_ul, 0, sizeof(struct ctrl_ul));
                 }
@@ -1433,6 +1431,16 @@ static int __devinit nozomi_card_init(struct pci_dev *pdev,
                 goto err_free_sbuf;
         }
 
+        for (i = PORT_MDM; i < MAX_PORT; i++) {
+                if (kfifo_alloc(&dc->port[i].fifo_ul,
+                      FIFO_BUFFER_SIZE_UL, GFP_ATOMIC)) {
+                        dev_err(&pdev->dev,
+                                        "Could not allocate kfifo buffer\n");
+                        ret = -ENOMEM;
+                        goto err_free_kfifo;
+                }
+        }
+
         spin_lock_init(&dc->spin_mutex);
 
         nozomi_setup_private_data(dc);
@@ -1445,7 +1453,7 @@ static int __devinit nozomi_card_init(struct pci_dev *pdev,
                         NOZOMI_NAME, dc);
         if (unlikely(ret)) {
                 dev_err(&pdev->dev, "can't request irq %d\n", pdev->irq);
-                goto err_free_sbuf;
+                goto err_free_kfifo;
         }
 
         DBG1("base_addr: %p", dc->base_addr);
@@ -1464,13 +1472,28 @@ static int __devinit nozomi_card_init(struct pci_dev *pdev,
         dc->state = NOZOMI_STATE_ENABLED;
 
         for (i = 0; i < MAX_PORT; i++) {
+                struct device *tty_dev;
+
                 mutex_init(&dc->port[i].tty_sem);
                 tty_port_init(&dc->port[i].port);
-                tty_register_device(ntty_driver, dc->index_start + i,
+                tty_dev = tty_register_device(ntty_driver, dc->index_start + i,
                                                         &pdev->dev);
+
+                if (IS_ERR(tty_dev)) {
+                        ret = PTR_ERR(tty_dev);
+                        dev_err(&pdev->dev, "Could not allocate tty?\n");
+                        goto err_free_tty;
+                }
         }
+
         return 0;
 
+err_free_tty:
+        for (i = dc->index_start; i < dc->index_start + MAX_PORT; ++i)
+                tty_unregister_device(ntty_driver, i);
+err_free_kfifo:
+        for (i = 0; i < MAX_PORT; i++)
+                kfifo_free(&dc->port[i].fifo_ul);
 err_free_sbuf:
         kfree(dc->send_buf);
         iounmap(dc->base_addr);
diff --git a/drivers/infiniband/hw/cxgb3/cxio_resource.c b/drivers/infiniband/hw/cxgb3/cxio_resource.c
index dcbf2606c438..31f9201b2980 100644
--- a/drivers/infiniband/hw/cxgb3/cxio_resource.c
+++ b/drivers/infiniband/hw/cxgb3/cxio_resource.c
@@ -86,8 +86,9 @@ static int __cxio_init_resource_fifo(struct kfifo *fifo,
                         kfifo_in(fifo, (unsigned char *) &i, sizeof(u32));
 
         for (i = 0; i < skip_low + skip_high; i++)
-                kfifo_out_locked(fifo, (unsigned char *) &entry,
-                                sizeof(u32), fifo_lock);
+                if (kfifo_out_locked(fifo, (unsigned char *) &entry,
+                                sizeof(u32), fifo_lock) != sizeof(u32))
+                                        break;
         return 0;
 }
 
diff --git a/drivers/media/video/meye.c b/drivers/media/video/meye.c
index 884a569d60a2..b421858ccf90 100644
--- a/drivers/media/video/meye.c
+++ b/drivers/media/video/meye.c
@@ -968,8 +968,9 @@ static int meyeioc_sync(struct file *file, void *fh, int *i)
                 /* fall through */
         case MEYE_BUF_DONE:
                 meye.grab_buffer[*i].state = MEYE_BUF_UNUSED;
-                kfifo_out_locked(&meye.doneq, (unsigned char *)&unused,
-                                sizeof(int), &meye.doneq_lock);
+                if (kfifo_out_locked(&meye.doneq, (unsigned char *)&unused,
+                                sizeof(int), &meye.doneq_lock) != sizeof(int))
+                                        break;
         }
         *i = meye.grab_buffer[*i].size;
         mutex_unlock(&meye.lock);
diff --git a/drivers/net/wireless/libertas/main.c b/drivers/net/wireless/libertas/main.c
index 2bcfa745524a..c2975c8e2f21 100644
--- a/drivers/net/wireless/libertas/main.c
+++ b/drivers/net/wireless/libertas/main.c
@@ -514,8 +514,10 @@ static int lbs_thread(void *data)
                 while (kfifo_len(&priv->event_fifo)) {
                         u32 event;
 
-                        kfifo_out(&priv->event_fifo, (unsigned char *) &event,
-                                sizeof(event));
+                        if (kfifo_out(&priv->event_fifo,
+                                (unsigned char *) &event, sizeof(event)) !=
+                                sizeof(event))
+                                        break;
                         spin_unlock_irq(&priv->driver_lock);
                         lbs_process_event(priv, event);
                         spin_lock_irq(&priv->driver_lock);
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
index d51ffeca2ec9..db6856c138fc 100644
--- a/drivers/scsi/libiscsi_tcp.c
+++ b/drivers/scsi/libiscsi_tcp.c
@@ -990,8 +990,13 @@ static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
                 }
 
                 if (r2t == NULL) {
-                        kfifo_out(&tcp_task->r2tqueue,
-                                    (void *)&tcp_task->r2t, sizeof(void *));
+                        if (kfifo_out(&tcp_task->r2tqueue,
+                            (void *)&tcp_task->r2t, sizeof(void *)) !=
+                            sizeof(void *)) {
+                                WARN_ONCE(1, "unexpected fifo state");
+                                r2t = NULL;
+                        }
+
                         r2t = tcp_task->r2t;
                 }
                 spin_unlock_bh(&session->lock);
diff --git a/drivers/scsi/libsrp.c b/drivers/scsi/libsrp.c
index 8424b8606efb..ab19b3b4be52 100644
--- a/drivers/scsi/libsrp.c
+++ b/drivers/scsi/libsrp.c
@@ -163,8 +163,11 @@ struct iu_entry *srp_iu_get(struct srp_target *target)
 {
         struct iu_entry *iue = NULL;
 
-        kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
-                        sizeof(void *), &target->iu_queue.lock);
+        if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
+                sizeof(void *), &target->iu_queue.lock) != sizeof(void *)) {
+                        WARN_ONCE(1, "unexpected fifo state");
+                        return NULL;
+        }
         if (!iue)
                 return iue;
         iue->target = target;
diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index 1b59c4a0e85f..5ed2565c89b6 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -56,7 +56,7 @@ extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer,
 extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size,
                         gfp_t gfp_mask);
 extern void kfifo_free(struct kfifo *fifo);
-extern __must_check unsigned int kfifo_in(struct kfifo *fifo,
+extern unsigned int kfifo_in(struct kfifo *fifo,
                                 const unsigned char *from, unsigned int len);
 extern __must_check unsigned int kfifo_out(struct kfifo *fifo,
                                 unsigned char *to, unsigned int len);
@@ -94,7 +94,7 @@ static inline unsigned int kfifo_len(struct kfifo *fifo)
  * the FIFO depending on the free space, and returns the number of
  * bytes copied.
  */
-static inline __must_check unsigned int kfifo_in_locked(struct kfifo *fifo,
+static inline unsigned int kfifo_in_locked(struct kfifo *fifo,
                 const unsigned char *from, unsigned int n, spinlock_t *lock)
 {
         unsigned long flags;