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authorRasmus Villemoes <linux@rasmusvillemoes.dk>2019-11-28 15:55:40 +0100
committerLi Yang <leoyang.li@nxp.com>2019-12-09 13:54:35 -0600
commit800cd6fb76f0ec7711deb72a86c924db1ae42648 (patch)
tree278e32e4f6c11a6bff5fcdd8f519bd9b666f354e /include/soc/fsl
parent09a39ec9decd99ef4dfaa21a83ce09f719495b49 (diff)
soc: fsl: qe: change return type of cpm_muram_alloc() to s32
There are a number of problems with cpm_muram_alloc() and its callers. Most callers assign the return value to some variable and then use IS_ERR_VALUE to check for allocation failure. However, when that variable is not sizeof(long), this leads to warnings - and it is indeed broken to do e.g. u32 foo = cpm_muram_alloc(); if (IS_ERR_VALUE(foo)) on a 64-bit platform, since the condition foo >= (unsigned long)-ENOMEM is tautologically false. There are also callers that ignore the possibility of error, and then there are those that check for error by comparing the return value to 0... One could fix that by changing all callers to store the return value temporarily in an "unsigned long" and test that. However, use of IS_ERR_VALUE() is error-prone and should be restricted to things which are inherently long-sized (stuff in pt_regs etc.). Instead, let's aim for changing to the standard kernel style int foo = cpm_muram_alloc(); if (foo < 0) deal_with_it() some->where = foo; Changing the return type from unsigned long to s32 (aka signed int) doesn't change the value that gets stored into any of the callers' variables except if the caller was storing the result in a u64 _and_ the allocation failed, so in itself this patch should be a no-op. Another problem with cpm_muram_alloc() is that it can certainly validly return 0 - and except if some cpm_muram_alloc_fixed() call interferes, the very first cpm_muram_alloc() call will return just that. But that shows that both ucc_slow_free() and ucc_fast_free() are buggy, since they assume that a value of 0 means "that field was never allocated". We'll later change cpm_muram_free() to accept (and ignore) a negative offset, so callers can use a sentinel of -1 instead of 0 and just unconditionally call cpm_muram_free(). Reviewed-by: Timur Tabi <timur@kernel.org> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Li Yang <leoyang.li@nxp.com>
Diffstat (limited to 'include/soc/fsl')
-rw-r--r--include/soc/fsl/qe/qe.h16
1 files changed, 8 insertions, 8 deletions
diff --git a/include/soc/fsl/qe/qe.h b/include/soc/fsl/qe/qe.h
index 521fa3a177e0..f589ae3f1216 100644
--- a/include/soc/fsl/qe/qe.h
+++ b/include/soc/fsl/qe/qe.h
@@ -98,26 +98,26 @@ static inline void qe_reset(void) {}
int cpm_muram_init(void);
#if defined(CONFIG_CPM) || defined(CONFIG_QUICC_ENGINE)
-unsigned long cpm_muram_alloc(unsigned long size, unsigned long align);
-int cpm_muram_free(unsigned long offset);
-unsigned long cpm_muram_alloc_fixed(unsigned long offset, unsigned long size);
+s32 cpm_muram_alloc(unsigned long size, unsigned long align);
+int cpm_muram_free(s32 offset);
+s32 cpm_muram_alloc_fixed(unsigned long offset, unsigned long size);
void __iomem *cpm_muram_addr(unsigned long offset);
unsigned long cpm_muram_offset(void __iomem *addr);
dma_addr_t cpm_muram_dma(void __iomem *addr);
#else
-static inline unsigned long cpm_muram_alloc(unsigned long size,
- unsigned long align)
+static inline s32 cpm_muram_alloc(unsigned long size,
+ unsigned long align)
{
return -ENOSYS;
}
-static inline int cpm_muram_free(unsigned long offset)
+static inline int cpm_muram_free(s32 offset)
{
return -ENOSYS;
}
-static inline unsigned long cpm_muram_alloc_fixed(unsigned long offset,
- unsigned long size)
+static inline s32 cpm_muram_alloc_fixed(unsigned long offset,
+ unsigned long size)
{
return -ENOSYS;
}