From 5f97b616e2e16682989f6639dd5b4025b4b01b68 Mon Sep 17 00:00:00 2001 From: Joy Chakraborty Date: Fri, 28 Jun 2024 12:37:01 +0100 Subject: [PATCH] nvmem: rmem: Fix return value of rmem_read() commit 28b008751aa295612318a0fbb2f22dd4f6a83139 upstream. reg_read() callback registered with nvmem core expects 0 on success and a negative value on error but rmem_read() returns the number of bytes read which is treated as an error at the nvmem core. This does not break when rmem is accessed using sysfs via bin_attr_nvmem_read()/write() but causes an error when accessed from places like nvmem_access_with_keepouts(), etc. Change to return 0 on success and error in case memory_read_from_buffer() returns an error or -EIO if bytes read do not match what was requested. Fixes: 5a3fa75a4d9c ("nvmem: Add driver to expose reserved memory as nvmem") Cc: stable@vger.kernel.org Signed-off-by: Joy Chakraborty Reviewed-by: Dan Carpenter Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20240628113704.13742-2-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/nvmem/rmem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/nvmem/rmem.c b/drivers/nvmem/rmem.c index 752d0bf4445e..7f907c5a445e 100644 --- a/drivers/nvmem/rmem.c +++ b/drivers/nvmem/rmem.c @@ -46,7 +46,10 @@ static int rmem_read(void *context, unsigned int offset, memunmap(addr); - return count; + if (count < 0) + return count; + + return count == bytes ? 0 : -EIO; } static int rmem_probe(struct platform_device *pdev)