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    Subject[PATCH] work around warning in i915_gem_gtt

    Gcc warns that addr might be used uninitialized. It may not, but I see
    why gcc gets confused.

    Additionally, hiding code with side-effects inside WARN_ON() argument
    seems uncool, so I moved it outside.

    Signed-off-by: Pavel Machek <pavel@ucw.cz>

    diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
    index 8b3cde7..8fcc974 100644
    --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
    +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
    @@ -1448,7 +1448,7 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm,
    (gen6_gtt_pte_t __iomem *)dev_priv->gtt.gsm + first_entry;
    int i = 0;
    struct sg_page_iter sg_iter;
    - dma_addr_t addr;
    + dma_addr_t addr = 0;

    for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) {
    addr = sg_page_iter_dma_address(&sg_iter);
    @@ -1462,9 +1462,10 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm,
    * of NUMA access patterns. Therefore, even with the way we assume
    * hardware should work, we must keep this posting read for paranoia.
    */
    - if (i != 0)
    - WARN_ON(readl(&gtt_entries[i-1]) !=
    - vm->pte_encode(addr, level, true));
    + if (i != 0) {
    + unsigned long gtt = readl(&gtt_entries[i-1]);
    + WARN_ON(gtt != vm->pte_encode(addr, level, true));
    + }

    /* This next bit makes the above posting read even more important. We
    * want to flush the TLBs only after we're certain all the PTE updates
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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