On 08/14/2014 04:16 PM, Matthew Wilcox wrote:
> On Thu, Aug 14, 2014 at 04:04:53PM +0300, Boaz Harrosh wrote:
>>> @@ -218,13 +218,13 @@ static long prd_direct_access(struct block_device *bdev, sector_t sector,
>>> {
>>> struct prd_device *prd = bdev->bd_disk->private_data;
>>>
>>> - if (!prd)
>>> + if (unlikely(!prd))
>>> return -ENODEV;
>>>
>>> *kaddr = prd_lookup_pg_addr(prd, sector);
>>> *pfn = prd_lookup_pfn(prd, sector);
>>>
>>> - return size;
>>> + return min_t(long, size, prd->size);
>>
>> This is off course a BUG need to subtract offset, will send version 2
>
> I was wondering about simplifying the return value for the drivers
> a little. Something like this:
>
Sure, looks good
I will produce a V2 for the brd-partitions set to send Jens, sometime
next week.
Thanks
Boaz
> diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
> index 741293f..8709b9f 100644
> --- a/arch/powerpc/sysdev/axonram.c
> +++ b/arch/powerpc/sysdev/axonram.c
> @@ -149,7 +149,7 @@ axon_ram_direct_access(struct block_device *device, sector_t sector,
> *kaddr = (void *)(bank->ph_addr + offset);
> *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
>
> - return min_t(long, size, bank->size - offset);
> + return bank->size - offset;
> }
>
> static const struct block_device_operations axon_ram_devops = {
> diff --git a/drivers/block/brd.c b/drivers/block/brd.c
> index 3483458..344681a 100644
> --- a/drivers/block/brd.c
> +++ b/drivers/block/brd.c
> @@ -384,9 +384,9 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector,
> *kaddr = page_address(page);
> *pfn = page_to_pfn(page);
>
> - /* Could optimistically check to see if the next page in the
> - * file is mapped to the next page of physical RAM */
> - return min_t(long, PAGE_SIZE, size);
> + /* If size > PAGE_SIZE, we could look to see if the next page in the
> + * file happens to be mapped to the next page of physical RAM */
> + return PAGE_SIZE;
> }
> #else
> #define brd_direct_access NULL
> diff --git a/drivers/block/prd.c b/drivers/block/prd.c
> index cc0aabf..1cfbd5b 100644
> --- a/drivers/block/prd.c
> +++ b/drivers/block/prd.c
> @@ -216,7 +216,7 @@ static long prd_direct_access(struct block_device *bdev, sector_t sector,
> *kaddr = prd_lookup_pg_addr(prd, sector);
> *pfn = prd_lookup_pfn(prd, sector);
>
> - return size;
> + return size - (sector * 512);
> }
>
> static const struct block_device_operations prd_fops = {
> diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
> index 2ee5556..96bc411 100644
> --- a/drivers/s390/block/dcssblk.c
> +++ b/drivers/s390/block/dcssblk.c
> @@ -881,7 +881,7 @@ dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
> *kaddr = (void *) (dev_info->start + offset);
> *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
>
> - return min_t(long, size, dev_sz - offset);
> + return dev_sz - offset;
> }
>
> static void
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 93ebdd53..ce3e69c 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -447,6 +447,7 @@ EXPORT_SYMBOL_GPL(bdev_write_page);
> long bdev_direct_access(struct block_device *bdev, sector_t sector,
> void **addr, unsigned long *pfn, long size)
> {
> + long max;
> const struct block_device_operations *ops = bdev->bd_disk->fops;
> if (!ops->direct_access)
> return -EOPNOTSUPP;
> @@ -456,8 +457,10 @@ long bdev_direct_access(struct block_device *bdev, sector_t sector,
> sector += get_start_sect(bdev);
> if (sector % (PAGE_SIZE / 512))
> return -EINVAL;
> - size = ops->direct_access(bdev, sector, addr, pfn, size);
> - return size ? size : -ERANGE;
> + max = ops->direct_access(bdev, sector, addr, pfn, size);
> + if (!max)
> + return -ERANGE;
> + return min(max, size);
> }
> EXPORT_SYMBOL_GPL(bdev_direct_access);
>
>
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