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IB/uverbs: New macro to set pointers to NULL if length is 0 in INIT_UDATA() 

Trying to have a ternary operator to choose between NULL (or 0) and the
real pointer value in invocations leads to an impossible choice between
a sparse error about a literal 0 used as a NULL pointer, and a gcc
warning about "pointer/integer type mismatch in conditional expression."

Rather than clutter the source with more casts, move the ternary
operator into a new INIT_UDATA_BUF_OR_NULL() macro, which makes it
easier to use and simplifies its callers.

Reported-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Roland Dreier 2013-12-19 08:37:03 -08:00
parent 309243ec14
commit a96e4e2ffe
2 changed files with 15 additions and 10 deletions
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8
drivers/infiniband/core/uverbs.h
View File

@ -55,6 +55,14 @@
(udata)->outlen = (olen); \
} while (0)
#define INIT_UDATA_BUF_OR_NULL(udata, ibuf, obuf, ilen, olen) \
do { \
(udata)->inbuf = (ilen) ? (const void __user *) (ibuf) : NULL; \
(udata)->outbuf = (olen) ? (void __user *) (obuf) : NULL; \
(udata)->inlen = (ilen); \
(udata)->outlen = (olen); \
} while (0)
/*
* Our lifetime rules for these structs are the following:
*

17
drivers/infiniband/core/uverbs_main.c
View File

@ -676,17 +676,14 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
return -EINVAL;
}
INIT_UDATA(&ucore,
(hdr.in_words) ? buf : 0,
(unsigned long)ex_hdr.response,
hdr.in_words * 8,
hdr.out_words * 8);
INIT_UDATA_BUF_OR_NULL(&ucore, buf, (unsigned long) ex_hdr.response,
hdr.in_words * 8, hdr.out_words * 8);
INIT_UDATA(&uhw,
(ex_hdr.provider_in_words) ? buf + ucore.inlen : 0,
(ex_hdr.provider_out_words) ? (unsigned long)ex_hdr.response + ucore.outlen : 0,
ex_hdr.provider_in_words * 8,
ex_hdr.provider_out_words * 8);
INIT_UDATA_BUF_OR_NULL(&uhw,
buf + ucore.inlen,
(unsigned long) ex_hdr.response + ucore.outlen,
ex_hdr.provider_in_words * 8,
ex_hdr.provider_out_words * 8);
err = uverbs_ex_cmd_table[command](file,
&ucore,