evie/android_kernel_oneplus_msm8998
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

nvmem: core: fix read buffer in place

Browse source 
[ Upstream commit 2fe518fecb3a4727393be286db9804cd82ee2d91 ]

When the bit_offset in the cell is zero, the pointer to the msb will
not be properly initialized (ie, will still be pointing to the first
byte in the buffer).

This being the case, if there are bits to clear in the msb, those will
be left untouched while the mask will incorrectly clear bit positions
on the first byte.

This commit also makes sure that any byte unused in the cell is
cleared.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jorge Ramirez-Ortiz 2019-04-13 11:32:58 +01:00 • committed by Greg Kroah-Hartman
parent 750c55e69c
commit 742cb74bf1
1 changed files with 10 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
drivers/nvmem/core.c
View file

@ -789,7 +789,7 @@ static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
void *buf)
{
u8 *p, *b;
int i, bit_offset = cell->bit_offset;
int i, extra, bit_offset = cell->bit_offset;
p = b = buf;
if (bit_offset) {
@ -804,11 +804,16 @@ static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
p = b;
*b++ >>= bit_offset;
}
/* result fits in less bytes */
if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
*p-- = 0;
} else {
/* point to the msb */
p += cell->bytes - 1;
}
/* result fits in less bytes */
extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
while (--extra >= 0)
*p-- = 0;
/* clear msb bits if any leftover in the last byte */
*p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
}