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Commit 8ea061bc authored by Bryan Mawhinney's avatar Bryan Mawhinney
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Prevent message overrun in LocklessCommandFifo. 

The previous logic in makeSpace and makeSpaceNonBlocking
was incorrect (probably a typo).  We shouldn't loop if
looping will overwrite unread messages, or if we would
make the buffer appear empty (mPut == mGet).

Change-Id: Iabc82ca94a585a7041069db97cbed7709f2d388f
parent bcdf40b4

libs/rs/rsLocklessFifo.cpp

+2 −3
Original line number Diff line number Diff line
@@ -166,7 +166,7 @@ bool LocklessCommandFifo::makeSpaceNonBlocking(uint32_t bytes) { 
    //dumpState("make space non-blocking");

    if ((mPut+bytes) > mEnd) {

        // Need to loop regardless of where get is.

        if ((mGet > mPut) && (mBuffer+4 >= mGet)) {

        if ((mGet > mPut) || (mBuffer+4 >= mGet)) {

            return false;

        }
@@ -189,7 +189,7 @@ void LocklessCommandFifo::makeSpace(uint32_t bytes) { 
    //dumpState("make space");

    if ((mPut+bytes) > mEnd) {

        // Need to loop regardless of where get is.

        while ((mGet > mPut) && (mBuffer+4 >= mGet)) {

        while ((mGet > mPut) || (mBuffer+4 >= mGet)) {

            usleep(100);

        }
@@ -210,4 +210,3 @@ void LocklessCommandFifo::makeSpace(uint32_t bytes) { 
void LocklessCommandFifo::dumpState(const char *s) const {

    LOGV("%s %p  put %p, get %p,  buf %p,  end %p", s, this, mPut, mGet, mBuffer, mEnd);

}