Messages in this thread | | | From | Nicolas Iooss <> | Subject | Uninitialized variable in bfad_im_bsg_els_ct_request | Date | Sun, 18 Dec 2016 21:44:33 +0100 |
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Hello,
Currently on Linus master tree and in linux-next [1], bfad_im_bsg_els_ct_request() code starts with the following code:
int bfad_im_bsg_els_ct_request(struct bsg_job *job) { /*...*/ struct fc_bsg_request *bsg_request = bsg_request; struct fc_bsg_reply *bsg_reply = job->reply; uint32_t command_type = bsg_request->msgcode;
The local variable "bsg_request" is initialized to itself (which would usually mean it is uninitialized) but it is dereferenced in order to get its "msgcode" field. As I am quite new to the kernel code and dereferencing self-initialized local variables looks black magic to me, could you please describe why this code is valid?
It has recently been introduced by commit 01e0e15c8b3b ("scsi: don't use fc_bsg_job::request and fc_bsg_job::reply directly").
Thanks, Nicolas Iooss
[1] https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/scsi/bfa/bfad_bsg.c?id=06548160dfecd1983ffd9d6795242a5cda095da5#n3356
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