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>

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;
@@ -141,17 +138,14 @@ 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)
 		return;
 
 	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;
 }
@@ -161,18 +155,14 @@ 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)
 		phys_addr = (~0UL);
 	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);

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);

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);

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);