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IB/hfi1: Combine shift copy and byte copy for SGE reads
Prevent over-reading the SGE length by using byte reads for non quad-word reads. Reviewed-by: Dean Luick <dean.luick@intel.com> Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Sebastian Sanchez
Doug Ledford
parent
a4309d94f7
commit
61868fb5c2
@ -165,9 +165,6 @@ void pio_copy(struct hfi1_devdata *dd, struct pio_buf *pbuf, u64 pbc,
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preempt_enable();
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}
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/* USE_SHIFTS is faster in user-space tests on a Xeon X5570 @ 2.93GHz */
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#define USE_SHIFTS 1
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#ifdef USE_SHIFTS
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/*
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* Handle carry bytes using shifts and masks.
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*
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@ -187,37 +184,55 @@ void pio_copy(struct hfi1_devdata *dd, struct pio_buf *pbuf, u64 pbc,
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#define mshift(x) (8 * (x))
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/*
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* Read nbytes bytes from "from" and return them in the LSB bytes
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* of pbuf->carry. Other bytes are zeroed. Any previous value
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* pbuf->carry is lost.
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* Jump copy - no-loop copy for < 8 bytes.
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*/
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static inline void jcopy(u8 *dest, const u8 *src, u32 n)
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{
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switch (n) {
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case 7:
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*dest++ = *src++;
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/* fall through */
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case 6:
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*dest++ = *src++;
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/* fall through */
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case 5:
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*dest++ = *src++;
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/* fall through */
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case 4:
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*dest++ = *src++;
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/* fall through */
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case 3:
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*dest++ = *src++;
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/* fall through */
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case 2:
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*dest++ = *src++;
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/* fall through */
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case 1:
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*dest++ = *src++;
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/* fall through */
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}
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}
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/*
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* Read nbytes from "from" and and place them in the low bytes
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* of pbuf->carry. Other bytes are left as-is. Any previous
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* value in pbuf->carry is lost.
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*
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* NOTES:
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* o do not read from from if nbytes is zero
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* o from may _not_ be u64 aligned
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* o nbytes must not span a QW boundary
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* o from may _not_ be u64 aligned.
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*/
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static inline void read_low_bytes(struct pio_buf *pbuf, const void *from,
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unsigned int nbytes)
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{
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unsigned long off;
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if (nbytes == 0) {
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pbuf->carry.val64 = 0;
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} else {
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/* align our pointer */
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off = (unsigned long)from & 0x7;
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from = (void *)((unsigned long)from & ~0x7l);
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pbuf->carry.val64 = ((*(u64 *)from)
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<< zshift(nbytes + off))/* zero upper bytes */
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>> zshift(nbytes); /* place at bottom */
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}
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pbuf->carry.val64 = 0;
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jcopy(&pbuf->carry.val8[0], from, nbytes);
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pbuf->carry_bytes = nbytes;
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}
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/*
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* Read nbytes bytes from "from" and put them at the next significant bytes
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* of pbuf->carry. Unused bytes are zeroed. It is expected that the extra
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* read does not overfill carry.
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* Read nbytes bytes from "from" and put them at the end of pbuf->carry.
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* It is expected that the extra read does not overfill carry.
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*
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* NOTES:
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* o from may _not_ be u64 aligned
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@ -226,31 +241,8 @@ static inline void read_low_bytes(struct pio_buf *pbuf, const void *from,
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static inline void read_extra_bytes(struct pio_buf *pbuf,
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const void *from, unsigned int nbytes)
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{
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unsigned long off = (unsigned long)from & 0x7;
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unsigned int room, xbytes;
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/* align our pointer */
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from = (void *)((unsigned long)from & ~0x7l);
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/* check count first - don't read anything if count is zero */
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while (nbytes) {
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/* find the number of bytes in this u64 */
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room = 8 - off; /* this u64 has room for this many bytes */
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xbytes = min(room, nbytes);
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/*
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* shift down to zero lower bytes, shift up to zero upper
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* bytes, shift back down to move into place
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*/
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pbuf->carry.val64 |= (((*(u64 *)from)
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>> mshift(off))
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<< zshift(xbytes))
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>> zshift(xbytes + pbuf->carry_bytes);
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off = 0;
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pbuf->carry_bytes += xbytes;
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nbytes -= xbytes;
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from += sizeof(u64);
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}
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jcopy(&pbuf->carry.val8[pbuf->carry_bytes], from, nbytes);
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pbuf->carry_bytes += nbytes;
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}
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/*
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@ -299,112 +291,6 @@ static inline int carry_write8(struct pio_buf *pbuf, void __iomem *dest)
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return 0;
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}
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#else /* USE_SHIFTS */
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/*
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* Handle carry bytes using byte copies.
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*
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* NOTE: the value the unused portion of carry is left uninitialized.
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*/
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/*
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* Jump copy - no-loop copy for < 8 bytes.
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*/
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static inline void jcopy(u8 *dest, const u8 *src, u32 n)
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{
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switch (n) {
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case 7:
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*dest++ = *src++;
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case 6:
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*dest++ = *src++;
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case 5:
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*dest++ = *src++;
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case 4:
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*dest++ = *src++;
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case 3:
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*dest++ = *src++;
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case 2:
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*dest++ = *src++;
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case 1:
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*dest++ = *src++;
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}
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}
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/*
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* Read nbytes from "from" and and place them in the low bytes
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* of pbuf->carry. Other bytes are left as-is. Any previous
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* value in pbuf->carry is lost.
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*
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* NOTES:
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* o do not read from from if nbytes is zero
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* o from may _not_ be u64 aligned.
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*/
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static inline void read_low_bytes(struct pio_buf *pbuf, const void *from,
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unsigned int nbytes)
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{
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jcopy(&pbuf->carry.val8[0], from, nbytes);
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pbuf->carry_bytes = nbytes;
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}
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/*
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* Read nbytes bytes from "from" and put them at the end of pbuf->carry.
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* It is expected that the extra read does not overfill carry.
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*
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* NOTES:
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* o from may _not_ be u64 aligned
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* o nbytes may span a QW boundary
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*/
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static inline void read_extra_bytes(struct pio_buf *pbuf,
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const void *from, unsigned int nbytes)
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{
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jcopy(&pbuf->carry.val8[pbuf->carry_bytes], from, nbytes);
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pbuf->carry_bytes += nbytes;
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}
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/*
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* Write a quad word using parts of pbuf->carry and the next 8 bytes of src.
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* Put the unused part of the next 8 bytes of src into the low bytes of
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* pbuf->carry.
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*/
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static inline void merge_write8(
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struct pio_buf *pbuf,
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void *dest,
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const void *src)
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{
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u32 remainder = 8 - pbuf->carry_bytes;
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jcopy(&pbuf->carry.val8[pbuf->carry_bytes], src, remainder);
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writeq(pbuf->carry.val64, dest);
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jcopy(&pbuf->carry.val8[0], src + remainder, pbuf->carry_bytes);
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}
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/*
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* Write a quad word using all bytes of carry.
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*/
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static inline void carry8_write8(union mix carry, void *dest)
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{
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writeq(carry.val64, dest);
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}
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/*
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* Write a quad word using all the valid bytes of carry. If carry
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* has zero valid bytes, nothing is written.
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* Returns 0 on nothing written, non-zero on quad word written.
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*/
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static inline int carry_write8(struct pio_buf *pbuf, void *dest)
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{
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if (pbuf->carry_bytes) {
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u64 zero = 0;
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jcopy(&pbuf->carry.val8[pbuf->carry_bytes], (u8 *)&zero,
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8 - pbuf->carry_bytes);
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writeq(pbuf->carry.val64, dest);
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return 1;
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}
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return 0;
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}
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#endif /* USE_SHIFTS */
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/*
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* Segmented PIO Copy - start
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*
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