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AGP fix race condition between unmapping and freeing pages

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With Andi's clflush fixup, we were getting hangs on server exit, flushing the
mappings after freeing each page helped.

This showed up a race condition where the pages after being freed could be
reused before the agp mappings had been flushed.  Flushing after each single
page is a bad thing for future drm work, so make the page destroy a two pass
unmapping all the pages, flushing the mappings, and then destroying the pages.

Signed-off-by: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Dave Airlie 2007-10-15 10:19:16 +10:00 committed by Dave Airlie
parent 23fd50450a
commit a2721e998e
6 changed files with 48 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/char/agp/agp.h
View File

@ -58,6 +58,9 @@ struct gatt_mask {
* devices this will probably be ignored */
};
#define AGP_PAGE_DESTROY_UNMAP 1
#define AGP_PAGE_DESTROY_FREE 2
struct aper_size_info_8 {
int size;
int num_entries;
@ -113,7 +116,7 @@ struct agp_bridge_driver {
struct agp_memory *(*alloc_by_type) (size_t, int);
void (*free_by_type)(struct agp_memory *);
void *(*agp_alloc_page)(struct agp_bridge_data *);
void (*agp_destroy_page)(void *);
void (*agp_destroy_page)(void *, int flags);
int (*agp_type_to_mask_type) (struct agp_bridge_data *, int);
};
@ -267,7 +270,7 @@ int agp_generic_remove_memory(struct agp_memory *mem, off_t pg_start, int type);
struct agp_memory *agp_generic_alloc_by_type(size_t page_count, int type);
void agp_generic_free_by_type(struct agp_memory *curr);
void *agp_generic_alloc_page(struct agp_bridge_data *bridge);
void agp_generic_destroy_page(void *addr);
void agp_generic_destroy_page(void *addr, int flags);
void agp_free_key(int key);
int agp_num_entries(void);
u32 agp_collect_device_status(struct agp_bridge_data *bridge, u32 mode, u32 command);

13
drivers/char/agp/ali-agp.c
View File

@ -156,29 +156,34 @@ static void *m1541_alloc_page(struct agp_bridge_data *bridge)
return addr;
}
static void ali_destroy_page(void * addr)
static void ali_destroy_page(void * addr, int flags)
{
if (addr) {
if (flags & AGP_PAGE_DESTROY_UNMAP) {
global_cache_flush(); /* is this really needed? --hch */
agp_generic_destroy_page(addr);
agp_generic_destroy_page(addr, flags);
global_flush_tlb();
} else
agp_generic_destroy_page(addr, flags);
}
}
static void m1541_destroy_page(void * addr)
static void m1541_destroy_page(void * addr, int flags)
{
u32 temp;
if (addr == NULL)
return;
if (flags & AGP_PAGE_DESTROY_UNMAP) {
global_cache_flush();
pci_read_config_dword(agp_bridge->dev, ALI_CACHE_FLUSH_CTRL, &temp);
pci_write_config_dword(agp_bridge->dev, ALI_CACHE_FLUSH_CTRL,
(((temp & ALI_CACHE_FLUSH_ADDR_MASK) |
virt_to_gart(addr)) | ALI_CACHE_FLUSH_EN));
agp_generic_destroy_page(addr);
}
agp_generic_destroy_page(addr, flags);
}

12
drivers/char/agp/backend.c
View File

@ -189,9 +189,11 @@ static int agp_backend_initialize(struct agp_bridge_data *bridge)
err_out:
if (bridge->driver->needs_scratch_page) {
bridge->driver->agp_destroy_page(
gart_to_virt(bridge->scratch_page_real));
bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
AGP_PAGE_DESTROY_UNMAP);
flush_agp_mappings();
bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
AGP_PAGE_DESTROY_FREE);
}
if (got_gatt)
bridge->driver->free_gatt_table(bridge);
@ -215,9 +217,11 @@ static void agp_backend_cleanup(struct agp_bridge_data *bridge)
if (bridge->driver->agp_destroy_page &&
bridge->driver->needs_scratch_page) {
bridge->driver->agp_destroy_page(
gart_to_virt(bridge->scratch_page_real));
bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
AGP_PAGE_DESTROY_UNMAP);
flush_agp_mappings();
bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
AGP_PAGE_DESTROY_FREE);
}
}

11
drivers/char/agp/generic.c
View File

@ -195,9 +195,12 @@ void agp_free_memory(struct agp_memory *curr)
}
if (curr->page_count != 0) {
for (i = 0; i < curr->page_count; i++) {
curr->bridge->driver->agp_destroy_page(gart_to_virt(curr->memory[i]));
curr->bridge->driver->agp_destroy_page(gart_to_virt(curr->memory[i]), AGP_PAGE_DESTROY_UNMAP);
}
flush_agp_mappings();
for (i = 0; i < curr->page_count; i++) {
curr->bridge->driver->agp_destroy_page(gart_to_virt(curr->memory[i]), AGP_PAGE_DESTROY_FREE);
}
}
agp_free_key(curr->key);
agp_free_page_array(curr);
@ -1176,7 +1179,7 @@ void *agp_generic_alloc_page(struct agp_bridge_data *bridge)
EXPORT_SYMBOL(agp_generic_alloc_page);
void agp_generic_destroy_page(void *addr)
void agp_generic_destroy_page(void *addr, int flags)
{
struct page *page;
@ -1184,10 +1187,14 @@ void agp_generic_destroy_page(void *addr)
return;
page = virt_to_page(addr);
if (flags & AGP_PAGE_DESTROY_UNMAP)
unmap_page_from_agp(page);
if (flags & AGP_PAGE_DESTROY_FREE) {
put_page(page);
free_page((unsigned long)addr);
atomic_dec(&agp_bridge->current_memory_agp);
}
}
EXPORT_SYMBOL(agp_generic_destroy_page);

4
drivers/char/agp/i460-agp.c
View File

@ -536,10 +536,10 @@ static void *i460_alloc_page (struct agp_bridge_data *bridge)
return page;
}
static void i460_destroy_page (void *page)
static void i460_destroy_page (void *page, int flags)
{
if (I460_IO_PAGE_SHIFT <= PAGE_SHIFT) {
agp_generic_destroy_page(page);
agp_generic_destroy_page(page, flags);
global_flush_tlb();
}
}

6
drivers/char/agp/intel-agp.c
View File

@ -400,9 +400,11 @@ static void intel_i810_free_by_type(struct agp_memory *curr)
if (curr->page_count == 4)
i8xx_destroy_pages(gart_to_virt(curr->memory[0]));
else {
agp_bridge->driver->agp_destroy_page(
gart_to_virt(curr->memory[0]));
agp_bridge->driver->agp_destroy_page(gart_to_virt(curr->memory[0]),
AGP_PAGE_DESTROY_UNMAP);
global_flush_tlb();
agp_bridge->driver->agp_destroy_page(gart_to_virt(curr->memory[0]),
AGP_PAGE_DESTROY_FREE);
}
agp_free_page_array(curr);
}