ALSA: ctxfi - Fix Oops at mmapping

Replace a spinlock with a mutex protecting the vm block list at
mmap / munmap calls, which caused Oops like below:

BUG: sleeping function called from invalid context at mm/slub.c:1599
in_atomic(): 0, irqs_disabled(): 1, pid: 32065, name: xine
Pid: 32065, comm: xine Tainted: P           2.6.29.4-75.fc10.x86_64 #1
Call Trace:
  [<ffffffff81040685>] __might_sleep+0x105/0x10a
  [<ffffffff810c9fae>] kmem_cache_alloc+0x32/0xe2
  [<ffffffffa08e3110>] ct_vm_map+0xfa/0x19e [snd_ctxfi]
  [<ffffffffa08e1a07>] ct_map_audio_buffer+0x4c/0x76 [snd_ctxfi]
  [<ffffffffa08e2aa5>] atc_pcm_playback_prepare+0x1d7/0x2a8 [snd_ctxfi]
  [<ffffffff8105ef3f>] ? up_read+0x9/0xb
  [<ffffffff81186b61>] ? __up_read+0x7c/0x87
  [<ffffffffa08e36a6>] ct_pcm_playback_prepare+0x39/0x60 [snd_ctxfi]
  [<ffffffffa0886bcb>] snd_pcm_do_prepare+0x16/0x28 [snd_pcm]
  [<ffffffffa08867c7>] snd_pcm_action_single+0x2d/0x5b [snd_pcm]
  [<ffffffffa08881f3>] snd_pcm_action_nonatomic+0x52/0x6a [snd_pcm]
  [<ffffffffa088a723>] snd_pcm_common_ioctl1+0x404/0xc79 [snd_pcm]
  [<ffffffff810c52c8>] ? alloc_pages_current+0xb9/0xc2
  [<ffffffff810c9402>] ? new_slab+0x1a5/0x1cb
  [<ffffffff810ab9ea>] ? vma_prio_tree_insert+0x23/0xc1
  [<ffffffffa088b411>] snd_pcm_playback_ioctl1+0x213/0x230 [snd_pcm]
  [<ffffffff810b6c20>] ? mmap_region+0x397/0x4c9
  [<ffffffffa088bd9b>] snd_pcm_playback_ioctl+0x2e/0x36 [snd_pcm]
  [<ffffffff810ddc64>] vfs_ioctl+0x2a/0x78
  [<ffffffff810de130>] do_vfs_ioctl+0x462/0x4a2
  [<ffffffff81029cef>] ? default_spin_lock_flags+0x9/0xe
  [<ffffffff81374647>] ? trace_hardirqs_off_thunk+0x3a/0x6c
  [<ffffffff810de1c5>] sys_ioctl+0x55/0x77
  [<ffffffff8101133a>] system_call_fastpath+0x16/0x1b

Signed-off-by: Takashi Iwai <tiwai@suse.de>

4 files changed, 13 insertions, 16 deletions

diff --git a/sound/pci/ctxfi/ctatc.c b/sound/pci/ctxfi/ctatc.c
index ead104ea1e35..1a4bb357eaef 100644
--- a/sound/pci/ctxfi/ctatc.c
+++ b/sound/pci/ctxfi/ctatc.c
@@ -119,7 +119,6 @@ atc_pcm_release_resources(struct ct_atc *atc, struct ct_atc_pcm *apcm);
 
 static int ct_map_audio_buffer(struct ct_atc *atc, struct ct_atc_pcm *apcm)
 {
-        unsigned long flags;
         struct snd_pcm_runtime *runtime;
         struct ct_vm *vm;
 
@@ -129,9 +128,7 @@ static int ct_map_audio_buffer(struct ct_atc *atc, struct ct_atc_pcm *apcm)
         runtime = apcm->substream->runtime;
         vm = atc->vm;
 
-        spin_lock_irqsave(&atc->vm_lock, flags);
         apcm->vm_block = vm->map(vm, runtime->dma_area, runtime->dma_bytes);
-        spin_unlock_irqrestore(&atc->vm_lock, flags);
 
         if (NULL == apcm->vm_block)
                 return -ENOENT;
@@ -141,7 +138,6 @@ static int ct_map_audio_buffer(struct ct_atc *atc, struct ct_atc_pcm *apcm)
 
 static void ct_unmap_audio_buffer(struct ct_atc *atc, struct ct_atc_pcm *apcm)
 {
-        unsigned long flags;
         struct ct_vm *vm;
 
         if (NULL == apcm->vm_block)
@@ -149,9 +145,7 @@ static void ct_unmap_audio_buffer(struct ct_atc *atc, struct ct_atc_pcm *apcm)
 
         vm = atc->vm;
 
-        spin_lock_irqsave(&atc->vm_lock, flags);
         vm->unmap(vm, apcm->vm_block);
-        spin_unlock_irqrestore(&atc->vm_lock, flags);
 
         apcm->vm_block = NULL;
 }
@@ -161,9 +155,7 @@ static unsigned long atc_get_ptp_phys(struct ct_atc *atc, int index)
         struct ct_vm *vm;
         void *kvirt_addr;
         unsigned long phys_addr;
-        unsigned long flags;
 
-        spin_lock_irqsave(&atc->vm_lock, flags);
         vm = atc->vm;
         kvirt_addr = vm->get_ptp_virt(vm, index);
         if (kvirt_addr == NULL)
@@ -171,8 +163,6 @@ static unsigned long atc_get_ptp_phys(struct ct_atc *atc, int index)
         else
                 phys_addr = virt_to_phys(kvirt_addr);
 
-        spin_unlock_irqrestore(&atc->vm_lock, flags);
-
         return phys_addr;
 }
 
@@ -1562,7 +1552,6 @@ int ct_atc_create(struct snd_card *card, struct pci_dev *pci,
         atc_set_ops(atc);
 
         spin_lock_init(&atc->atc_lock);
-        spin_lock_init(&atc->vm_lock);
 
         /* Find card model */
         err = atc_identify_card(atc);
diff --git a/sound/pci/ctxfi/ctatc.h b/sound/pci/ctxfi/ctatc.h
index 286c993d461a..a7b0ec24cd75 100644
--- a/sound/pci/ctxfi/ctatc.h
+++ b/sound/pci/ctxfi/ctatc.h
@@ -101,7 +101,6 @@ struct ct_atc {
         unsigned long (*get_ptp_phys)(struct ct_atc *atc, int index);
 
         spinlock_t atc_lock;
-        spinlock_t vm_lock;
 
         int (*pcm_playback_prepare)(struct ct_atc *atc,
                                     struct ct_atc_pcm *apcm);
diff --git a/sound/pci/ctxfi/ctvmem.c b/sound/pci/ctxfi/ctvmem.c
index cecf77e3ee86..363b67e3a9e7 100644
--- a/sound/pci/ctxfi/ctvmem.c
+++ b/sound/pci/ctxfi/ctvmem.c
@@ -35,25 +35,27 @@ get_vm_block(struct ct_vm *vm, unsigned int size)
         struct ct_vm_block *block = NULL, *entry = NULL;
         struct list_head *pos = NULL;
 
+        mutex_lock(&vm->lock);
         list_for_each(pos, &vm->unused) {
                 entry = list_entry(pos, struct ct_vm_block, list);
                 if (entry->size >= size)
                         break; /* found a block that is big enough */
         }
         if (pos == &vm->unused)
-                return NULL;
+                goto out;
 
         if (entry->size == size) {
                 /* Move the vm node from unused list to used list directly */
                 list_del(&entry->list);
                 list_add(&entry->list, &vm->used);
                 vm->size -= size;
-                return entry;
+                block = entry;
+                goto out;
         }
 
         block = kzalloc(sizeof(*block), GFP_KERNEL);
         if (NULL == block)
-                return NULL;
+                goto out;
 
         block->addr = entry->addr;
         block->size = size;
@@ -62,6 +64,8 @@ get_vm_block(struct ct_vm *vm, unsigned int size)
         entry->size -= size;
         vm->size -= size;
 
+ out:
+        mutex_unlock(&vm->lock);
         return block;
 }
 
@@ -70,6 +74,7 @@ static void put_vm_block(struct ct_vm *vm, struct ct_vm_block *block)
         struct ct_vm_block *entry = NULL, *pre_ent = NULL;
         struct list_head *pos = NULL, *pre = NULL;
 
+        mutex_lock(&vm->lock);
         list_del(&block->list);
         vm->size += block->size;
 
@@ -106,6 +111,7 @@ static void put_vm_block(struct ct_vm *vm, struct ct_vm_block *block)
                 pos = pre;
                 pre = pos->prev;
         }
+        mutex_unlock(&vm->lock);
 }
 
 /* Map host addr (kmalloced/vmalloced) to device logical addr. */
@@ -191,6 +197,8 @@ int ct_vm_create(struct ct_vm **rvm)
         if (NULL == vm)
                 return -ENOMEM;
 
+        mutex_init(&vm->lock);
+
         /* Allocate page table pages */
         for (i = 0; i < CT_PTP_NUM; i++) {
                 vm->ptp[i] = kmalloc(PAGE_SIZE, GFP_KERNEL);
diff --git a/sound/pci/ctxfi/ctvmem.h b/sound/pci/ctxfi/ctvmem.h
index 4eb5bdd5cad4..618952efa5b3 100644
--- a/sound/pci/ctxfi/ctvmem.h
+++ b/sound/pci/ctxfi/ctvmem.h
@@ -20,7 +20,7 @@
 
 #define CT_PTP_NUM      1       /* num of device page table pages */
 
-#include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/list.h>
 
 struct ct_vm_block {
@@ -35,6 +35,7 @@ struct ct_vm {
         unsigned int size;              /* Available addr space in bytes */
         struct list_head unused;        /* List of unused blocks */
         struct list_head used;          /* List of used blocks */
+        struct mutex lock;
 
         /* Map host addr (kmalloced/vmalloced) to device logical addr. */
         struct ct_vm_block *(*map)(struct ct_vm *, void *host_addr, int size);