diff mbox series

[1/5] swiotlb: Introduce swiotlb_max_mapping_size()

Message ID 20190123163049.24863-2-joro@8bytes.org (mailing list archive)
State New, archived
Headers show
Series Fix virtio-blk issue with SWIOTLB | expand

Commit Message

Joerg Roedel Jan. 23, 2019, 4:30 p.m. UTC 
From: Joerg Roedel <jroedel@suse.de>

The function returns the maximum size that can be remapped
by the SWIOTLB implementation. This function will be later
exposed to users through the DMA-API.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/swiotlb.h | 5 +++++
 kernel/dma/swiotlb.c    | 5 +++++
 2 files changed, 10 insertions(+)

Comments

Christoph Hellwig Jan. 23, 2019, 9:28 p.m. UTC | #1 
On Wed, Jan 23, 2019 at 05:30:45PM +0100, Joerg Roedel wrote:
> +extern size_t swiotlb_max_mapping_size(struct device *dev);

No need for the extern keyword on function declarations in headers.
Joerg Roedel Jan. 24, 2019, 8:24 a.m. UTC | #2 
On Wed, Jan 23, 2019 at 10:28:13PM +0100, Christoph Hellwig wrote:
> On Wed, Jan 23, 2019 at 05:30:45PM +0100, Joerg Roedel wrote:
> > +extern size_t swiotlb_max_mapping_size(struct device *dev);
> 
> No need for the extern keyword on function declarations in headers.

Right, but all other function declarations in that header file have
'extern' too, so I added it also for that one.

Regards,

	Joerg
Christoph Hellwig Jan. 24, 2019, 8:47 a.m. UTC | #3 
On Thu, Jan 24, 2019 at 09:24:31AM +0100, Joerg Roedel wrote:
> On Wed, Jan 23, 2019 at 10:28:13PM +0100, Christoph Hellwig wrote:
> > On Wed, Jan 23, 2019 at 05:30:45PM +0100, Joerg Roedel wrote:
> > > +extern size_t swiotlb_max_mapping_size(struct device *dev);
> > 
> > No need for the extern keyword on function declarations in headers.
> 
> Right, but all other function declarations in that header file have
> 'extern' too, so I added it also for that one.

Your patch 3 also doesn't use an extern.  And I have to say I
much prefer it that way..
diff mbox series

Patch

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 7c007ed7505f..ceb623321f38 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -62,6 +62,7 @@  extern void swiotlb_tbl_sync_single(struct device *hwdev,
 
 extern int
 swiotlb_dma_supported(struct device *hwdev, u64 mask);
+extern size_t swiotlb_max_mapping_size(struct device *dev);
 
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
@@ -95,6 +96,10 @@  static inline unsigned int swiotlb_max_segment(void)
 {
 	return 0;
 }
+static inline size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	return SIZE_MAX;
+}
 #endif /* CONFIG_SWIOTLB */
 
 extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1fb6fd68b9c7..9cb21259cb0b 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -662,3 +662,8 @@  swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
 	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
 }
+
+size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
+}