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Fix a case where a request frame can be composed that requires 2 or more

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SGList elements, but there's only enough space in the request frame for
either 1 element or a chain frame pointer.  Previously, the code would
hit the wrong case, add the SGList element, but then fail to add the
chain frame due to lack of space.  Re-arrange the code to catch this case
earlier and handle it.

Sponsored by:	Netflix
This commit is contained in:
Scott Long 2018-02-06 06:55:55 +00:00
parent 99e7a4ad9e
commit 4b07a5606c
1 changed files with 11 additions and 11 deletions
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22
sys/dev/mps/mps.c
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@ -2609,6 +2609,17 @@ mps_push_sge(struct mps_command *cm, void *sgep, size_t len, int segsleft)
if (cm->cm_sglsize < MPS_SGC_SIZE) if (cm->cm_sglsize < MPS_SGC_SIZE)
panic("MPS: Need SGE Error Code\n"); panic("MPS: Need SGE Error Code\n");
if (segsleft >= 1 && cm->cm_sglsize < len + MPS_SGC_SIZE) {
/*
* 1 or more segment, enough room for only a chain.
* Hope the previous element wasn't a Simple entry
* that needed to be marked with
* MPI2_SGE_FLAGS_LAST_ELEMENT. Case (4).
*/
if ((error = mps_add_chain(cm)) != 0)
return (error);
}
if (segsleft >= 2 && if (segsleft >= 2 &&
cm->cm_sglsize < len + MPS_SGC_SIZE + MPS_SGE64_SIZE) { cm->cm_sglsize < len + MPS_SGC_SIZE + MPS_SGE64_SIZE) {
/* /*
@ -2633,17 +2644,6 @@ mps_push_sge(struct mps_command *cm, void *sgep, size_t len, int segsleft)
return (mps_add_chain(cm)); return (mps_add_chain(cm));
} }
if (segsleft >= 1 && cm->cm_sglsize < len + MPS_SGC_SIZE) {
/*
* 1 or more segment, enough room for only a chain.
* Hope the previous element wasn't a Simple entry
* that needed to be marked with
* MPI2_SGE_FLAGS_LAST_ELEMENT. Case (4).
*/
if ((error = mps_add_chain(cm)) != 0)
return (error);
}
#ifdef INVARIANTS #ifdef INVARIANTS
/* Case 1: 1 more segment, enough room for it. */ /* Case 1: 1 more segment, enough room for it. */
if (segsleft == 1 && cm->cm_sglsize < len) if (segsleft == 1 && cm->cm_sglsize < len)