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[5/7] mmc: omap: Map the virtual page for PIO

Message ID 20240125-mmc-proper-kmap-v1-5-ba953c1ac3f9@linaro.org (mailing list archive)
State New, archived
Headers show
Series mmc: Try to do proper kmap_local() for scatterlists | expand

Commit Message

Linus Walleij Jan. 25, 2024, 2:37 p.m. UTC 
Use kmap_local_page() instead of sg_virt() to obtain a page
from the scatterlist: sg_virt() will not perform bounce
buffering if the page happens to be located in high memory,
which the driver may or may not be using.

Suggested-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-mmc/20240122073423.GA25859@lst.de/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/mmc/host/omap.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index 9fb8995b43a1..3e36480b22ad 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -659,7 +659,7 @@  mmc_omap_sg_to_buf(struct mmc_omap_host *host)
 
 	sg = host->data->sg + host->sg_idx;
 	host->buffer_bytes_left = sg->length;
-	host->buffer = sg_virt(sg);
+	host->buffer = kmap_local_page(sg_page(sg));
 	if (host->buffer_bytes_left > host->total_bytes_left)
 		host->buffer_bytes_left = host->total_bytes_left;
 }
@@ -691,6 +691,11 @@  mmc_omap_xfer_data(struct mmc_omap_host *host, int write)
 	nwords = DIV_ROUND_UP(n, 2);
 
 	host->buffer_bytes_left -= n;
+	if (host->buffer_bytes_left == 0) {
+		kunmap_local(host->buffer);
+		host->buffer = NULL;
+	}
+
 	host->total_bytes_left -= n;
 	host->data->bytes_xfered += n;