Re: [PATCH 1/2] mmc: let the dma map ops handle bouncing
On Tue, 25 Jun 2019 at 11:21, Christoph Hellwig wrote:
>
> Just like we do for all other block drivers. Especially as the limit
> imposed at the moment might be way to pessimistic for iommus.
>
> Signed-off-by: Christoph Hellwig
>From your earlier reply, I decided to fold in the following
information to the changelog, as to clarify things a bit:
"This also means we are not going to set a bounce limit for the queue, in
case we have a dma mask. On most architectures it was never needed, the
major hold out was x86-32 with PAE, but that has been fixed by now."
Please tell, if you want me to change something.
Applied for next, thanks!
Kind regards
Uffe
> ---
> drivers/mmc/core/queue.c | 7 ++-
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
> index 3557d5c51141..e327f80ebe70 100644
> --- a/drivers/mmc/core/queue.c
> +++ b/drivers/mmc/core/queue.c
> @@ -350,18 +350,15 @@ static const struct blk_mq_ops mmc_mq_ops = {
> static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
> {
> struct mmc_host *host = card->host;
> - u64 limit = BLK_BOUNCE_HIGH;
> unsigned block_size = 512;
>
> - if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
> - limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
> -
> blk_queue_flag_set(QUEUE_FLAG_NONROT, mq->queue);
> blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, mq->queue);
> if (mmc_can_erase(card))
> mmc_queue_setup_discard(mq->queue, card);
>
> - blk_queue_bounce_limit(mq->queue, limit);
> + if (!mmc_dev(host)->dma_mask || !*mmc_dev(host)->dma_mask)
> + blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
> blk_queue_max_hw_sectors(mq->queue,
> min(host->max_blk_count, host->max_req_size / 512));
> blk_queue_max_segments(mq->queue, host->max_segs);
> --
> 2.20.1
>
[PATCH 1/2] mmc: let the dma map ops handle bouncing
Just like we do for all other block drivers. Especially as the limit
imposed at the moment might be way to pessimistic for iommus.
Signed-off-by: Christoph Hellwig
---
drivers/mmc/core/queue.c | 7 ++-
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 3557d5c51141..e327f80ebe70 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -350,18 +350,15 @@ static const struct blk_mq_ops mmc_mq_ops = {
static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
{
struct mmc_host *host = card->host;
- u64 limit = BLK_BOUNCE_HIGH;
unsigned block_size = 512;
- if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
- limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
-
blk_queue_flag_set(QUEUE_FLAG_NONROT, mq->queue);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, mq->queue);
if (mmc_can_erase(card))
mmc_queue_setup_discard(mq->queue, card);
- blk_queue_bounce_limit(mq->queue, limit);
+ if (!mmc_dev(host)->dma_mask || !*mmc_dev(host)->dma_mask)
+ blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
blk_queue_max_hw_sectors(mq->queue,
min(host->max_blk_count, host->max_req_size / 512));
blk_queue_max_segments(mq->queue, host->max_segs);
--
2.20.1
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Re: [PATCH 1/2] mmc: let the dma map ops handle bouncing
On Thu, Apr 11, 2019 at 11:00:56AM +0200, Ulf Hansson wrote: > > blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, mq->queue); > > if (mmc_can_erase(card)) > > mmc_queue_setup_discard(mq->queue, card); > > > > - blk_queue_bounce_limit(mq->queue, limit); > > + if (!mmc_dev(host)->dma_mask || !*mmc_dev(host)->dma_mask) > > + blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH); > > So this means we are not going to set a bounce limit for the queue, in > case we have a dma mask. > > Why isn't that needed no more? Whats has changed? On most architectures it was never needed, the major hold out was x86-32 with PAE. In general the dma_mask tells the DMA API layer what is supported, and if the physical addressing doesn't support that it has to use bounce buffering like swiotlb (or dmabounce on arm32). A couple month ago I finally fixes x86-32 to also properly set up swiotlb, and remove the block layerer bounce buffering that wasn't for highmem (which is about having a kernel mapping, not addressing), and ISA DMA (which is not handled like everything else, but we'll get there). But for some reason I missed mmc back then, so mmc right now is the only remaining user of address based block layer bouncing. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH 1/2] mmc: let the dma map ops handle bouncing
Hi Christoph,
On Thu, 11 Apr 2019 at 09:10, Christoph Hellwig wrote:
>
> Just like we do for all other block drivers. Especially as the limit
> imposed at the moment might be way to pessimistic for iommus.
I would appreciate some information in the changelog, as it's quite
unclear of what this change really means.
>
> Signed-off-by: Christoph Hellwig
> ---
> drivers/mmc/core/queue.c | 7 ++-
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
> index 7c364a9c4eeb..eb9c0692062c 100644
> --- a/drivers/mmc/core/queue.c
> +++ b/drivers/mmc/core/queue.c
> @@ -354,18 +354,15 @@ static const struct blk_mq_ops mmc_mq_ops = {
> static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
> {
> struct mmc_host *host = card->host;
> - u64 limit = BLK_BOUNCE_HIGH;
> unsigned block_size = 512;
>
> - if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
> - limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
> -
> blk_queue_flag_set(QUEUE_FLAG_NONROT, mq->queue);
> blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, mq->queue);
> if (mmc_can_erase(card))
> mmc_queue_setup_discard(mq->queue, card);
>
> - blk_queue_bounce_limit(mq->queue, limit);
> + if (!mmc_dev(host)->dma_mask || !*mmc_dev(host)->dma_mask)
> + blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
So this means we are not going to set a bounce limit for the queue, in
case we have a dma mask.
Why isn't that needed no more? Whats has changed?
> blk_queue_max_hw_sectors(mq->queue,
> min(host->max_blk_count, host->max_req_size / 512));
> blk_queue_max_segments(mq->queue, host->max_segs);
> --
> 2.20.1
>
Kind regards
Uffe
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[PATCH 1/2] mmc: let the dma map ops handle bouncing
Just like we do for all other block drivers. Especially as the limit
imposed at the moment might be way to pessimistic for iommus.
Signed-off-by: Christoph Hellwig
---
drivers/mmc/core/queue.c | 7 ++-
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 7c364a9c4eeb..eb9c0692062c 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -354,18 +354,15 @@ static const struct blk_mq_ops mmc_mq_ops = {
static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
{
struct mmc_host *host = card->host;
- u64 limit = BLK_BOUNCE_HIGH;
unsigned block_size = 512;
- if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
- limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
-
blk_queue_flag_set(QUEUE_FLAG_NONROT, mq->queue);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, mq->queue);
if (mmc_can_erase(card))
mmc_queue_setup_discard(mq->queue, card);
- blk_queue_bounce_limit(mq->queue, limit);
+ if (!mmc_dev(host)->dma_mask || !*mmc_dev(host)->dma_mask)
+ blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);
blk_queue_max_hw_sectors(mq->queue,
min(host->max_blk_count, host->max_req_size / 512));
blk_queue_max_segments(mq->queue, host->max_segs);
--
2.20.1
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