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nvmem: rmem: make ->reg_read() straight forward code

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memory_read_from_buffer() is a weird choice; it:
 - is made for iteration with ppos a pointer.
 - does futile error checking in our case.
 - does NOT ensure we read exactly N bytes.

Replace it by:
1. A check that (offset + bytes) lands inside the region and,
2. a plain memcpy().

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20241230143035.265518-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Théo Lebrun
2024-12-30 14:30:28 +00:00
committed by Greg Kroah-Hartman
parent 6fdbc7b9aa
commit 9c1d9de52b
1 changed files with 6 additions and 9 deletions
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15
drivers/nvmem/rmem.c
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@@ -21,10 +21,10 @@ static int rmem_read(void *context, unsigned int offset,
void *val, size_t bytes)
{
struct rmem *priv = context;
size_t available = priv->mem->size;
loff_t off = offset;
void *addr;
int count;
if ((phys_addr_t)offset + bytes > priv->mem->size)
return -EIO;
/*
* Only map the reserved memory at this point to avoid potential rogue
@@ -36,20 +36,17 @@ static int rmem_read(void *context, unsigned int offset,
* An alternative would be setting the memory as RO, set_memory_ro(),
* but as of Dec 2020 this isn't possible on arm64.
*/
addr = memremap(priv->mem->base, available, MEMREMAP_WB);
addr = memremap(priv->mem->base, priv->mem->size, MEMREMAP_WB);
if (!addr) {
dev_err(priv->dev, "Failed to remap memory region\n");
return -ENOMEM;
}
count = memory_read_from_buffer(val, bytes, &off, addr, available);
memcpy(val, addr + offset, bytes);
memunmap(addr);
if (count < 0)
return count;
return count == bytes ? 0 : -EIO;
return 0;
}
static int rmem_probe(struct platform_device *pdev)