pci=resource_alignment argument can override the default alignment for
the resource. The remainder code introduced in the commit 9036bd0efcb6
("PCI: Align head space better") can move remainder space (non-aligning
part of the size) before the aligning left edge which results in
violating the requested alignment.

Introduce struct pci_resreq_data to hold device and user-given alignment
to be able to honor it in pci_align_resource(). When user-given alignment
is found, any remainder movement is skipped.

Fixes: 9036bd0efcb6 ("PCI: Align head space better")
Reported-by: Sashiko <[email protected]>
Link: 
https://lore.kernel.org/linux-pci/[email protected]/
Signed-off-by: Ilpo Järvinen <[email protected]>
---

IMO, PPC rigging the user alignment override to enforce arch specific
min alignment is mixing things wrongly. It would be more appropriate
to do arch alignment overrides by overriding pci_resource_alignment().

Jani Nikula <[email protected]> did ack this with a condition that
there is a proper review done by somebody else so I've not yet included
his tag.

---
 arch/alpha/kernel/pci.c          |  3 ++-
 arch/arm/kernel/bios32.c         |  5 +++--
 arch/m68k/kernel/pcibios.c       |  4 ++--
 arch/mips/pci/pci-generic.c      |  5 +++--
 arch/mips/pci/pci-legacy.c       |  5 +++--
 arch/parisc/kernel/pci.c         |  5 +++--
 arch/powerpc/kernel/pci-common.c |  5 +++--
 arch/sh/drivers/pci/pci.c        |  5 +++--
 arch/x86/pci/i386.c              |  5 +++--
 arch/xtensa/kernel/pci.c         |  5 +++--
 drivers/char/agp/intel-gtt.c     |  5 ++++-
 drivers/gpu/drm/i915/i915_gmch.c |  5 +++--
 drivers/pci/pci.c                |  5 +++--
 drivers/pci/setup-res.c          | 19 +++++++++++++------
 include/linux/pci.h              | 32 ++++++++++++++++++++++++++++++--
 15 files changed, 81 insertions(+), 32 deletions(-)

diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c
index 11df411b1d18..c5d725a9781f 100644
--- a/arch/alpha/kernel/pci.c
+++ b/arch/alpha/kernel/pci.c
@@ -128,7 +128,8 @@ pcibios_align_resource(void *data, const struct resource 
*res,
                       const struct resource *empty_res,
                       resource_size_t size, resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        struct pci_controller *hose = dev->sysdata;
        unsigned long alignto;
        resource_size_t start = res->start;
diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
index ac0e890510da..3e61826f07fb 100644
--- a/arch/arm/kernel/bios32.c
+++ b/arch/arm/kernel/bios32.c
@@ -564,7 +564,8 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                       resource_size_t size,
                                       resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        resource_size_t start = res->start;
        struct pci_host_bridge *host_bridge;
 
@@ -578,7 +579,7 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                start, size, align);
 
        if (res->flags & IORESOURCE_MEM)
-               return pci_align_resource(dev, res, empty_res, size, align);
+               return pci_align_resource(rr, res, empty_res, size, align);
 
        return start;
 }
diff --git a/arch/m68k/kernel/pcibios.c b/arch/m68k/kernel/pcibios.c
index 7a9e60df79c5..3024408412bc 100644
--- a/arch/m68k/kernel/pcibios.c
+++ b/arch/m68k/kernel/pcibios.c
@@ -31,14 +31,14 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                       resource_size_t size,
                                       resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
        resource_size_t start = res->start;
 
        if ((res->flags & IORESOURCE_IO) && (start & 0x300))
                start = (start + 0x3ff) & ~0x3ff;
 
        if (res->flags & IORESOURCE_MEM)
-               return pci_align_resource(dev, res, empty_res, size, align);
+               return pci_align_resource(rr, res, empty_res, size, align);
 
        return start;
 }
diff --git a/arch/mips/pci/pci-generic.c b/arch/mips/pci/pci-generic.c
index c2e23d0c1d77..7f3ecb91b85b 100644
--- a/arch/mips/pci/pci-generic.c
+++ b/arch/mips/pci/pci-generic.c
@@ -25,7 +25,8 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                       const struct resource *empty_res,
                                       resource_size_t size, resource_size_t 
align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        resource_size_t start = res->start;
        struct pci_host_bridge *host_bridge;
 
@@ -39,7 +40,7 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                start, size, align);
 
        if (res->flags & IORESOURCE_MEM)
-               return pci_align_resource(dev, res, empty_res, size, align);
+               return pci_align_resource(rr, res, empty_res, size, align);
 
        return start;
 }
diff --git a/arch/mips/pci/pci-legacy.c b/arch/mips/pci/pci-legacy.c
index dae6dafdd6e0..82d4b01db64e 100644
--- a/arch/mips/pci/pci-legacy.c
+++ b/arch/mips/pci/pci-legacy.c
@@ -55,7 +55,8 @@ pcibios_align_resource(void *data, const struct resource *res,
                       const struct resource *empty_res,
                       resource_size_t size, resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        struct pci_controller *hose = dev->sysdata;
        resource_size_t start = res->start;
 
@@ -70,7 +71,7 @@ pcibios_align_resource(void *data, const struct resource *res,
                if (start & 0x300)
                        start = (start + 0x3ff) & ~0x3ff;
        } else if (res->flags & IORESOURCE_MEM) {
-               start = pci_align_resource(dev, res, empty_res, size, align);
+               start = pci_align_resource(rr, res, empty_res, size, align);
 
                /* Make sure we start at our min on all hoses */
                if (start < PCIBIOS_MIN_MEM + hose->mem_resource->start)
diff --git a/arch/parisc/kernel/pci.c b/arch/parisc/kernel/pci.c
index 96950fe9c2b7..36a3a439f609 100644
--- a/arch/parisc/kernel/pci.c
+++ b/arch/parisc/kernel/pci.c
@@ -193,7 +193,8 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                       resource_size_t size,
                                       resource_size_t alignment)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        resource_size_t align, start = res->start;
 
        pci_dbg(dev, "%pR: pcibios_align_resource(%lx, 0x%llx, 0x%llx)\n",
@@ -205,7 +206,7 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
        if (align > alignment)
                start = ALIGN(start, align);
        else
-               start = pci_align_resource(dev, res, empty_res, size, 
alignment);
+               start = pci_align_resource(rr, res, empty_res, size, alignment);
 
        return start;
 }
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 4fc52c21fe5d..23594759cfe2 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1131,7 +1131,8 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                       resource_size_t size,
                                       resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        resource_size_t start = res->start;
 
        if (res->flags & IORESOURCE_IO) {
@@ -1140,7 +1141,7 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                if (start & 0x300)
                        start = (start + 0x3ff) & ~0x3ff;
        } else if (res->flags & IORESOURCE_MEM) {
-               start = pci_align_resource(dev, res, empty_res, size, align);
+               start = pci_align_resource(rr, res, empty_res, size, align);
        }
 
        return start;
diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c
index 878a27a1acfb..279f2770ff4b 100644
--- a/arch/sh/drivers/pci/pci.c
+++ b/arch/sh/drivers/pci/pci.c
@@ -172,7 +172,8 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                                       resource_size_t size,
                                       resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        struct pci_channel *hose = dev->sysdata;
        resource_size_t start = res->start;
 
@@ -186,7 +187,7 @@ resource_size_t pcibios_align_resource(void *data, const 
struct resource *res,
                if (start & 0x300)
                        start = (start + 0x3ff) & ~0x3ff;
        } else if (res->flags & IORESOURCE_MEM) {
-               start = pci_align_resource(dev, res, empty_res, size, align);
+               start = pci_align_resource(rr, res, empty_res, size, align);
        }
 
        return start;
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index e2de26b82940..4178ae4380c2 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -156,7 +156,8 @@ pcibios_align_resource(void *data, const struct resource 
*res,
                       const struct resource *empty_res,
                       resource_size_t size, resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        resource_size_t start = res->start;
 
        if (res->flags & IORESOURCE_IO) {
@@ -165,7 +166,7 @@ pcibios_align_resource(void *data, const struct resource 
*res,
                if (start & 0x300)
                        start = (start + 0x3ff) & ~0x3ff;
        } else if (res->flags & IORESOURCE_MEM) {
-               start = pci_align_resource(dev, res, empty_res, size, align);
+               start = pci_align_resource(rr, res, empty_res, size, align);
 
                /* The low 1MB range is reserved for ISA cards */
                if (start < BIOS_END)
diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c
index 305031551136..4e8ad4a3c9fe 100644
--- a/arch/xtensa/kernel/pci.c
+++ b/arch/xtensa/kernel/pci.c
@@ -42,7 +42,8 @@ pcibios_align_resource(void *data, const struct resource *res,
                       const struct resource *empty_res,
                       resource_size_t size, resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
+       struct pci_dev *dev = rr->dev;
        resource_size_t start = res->start;
 
        if (res->flags & IORESOURCE_IO) {
@@ -55,7 +56,7 @@ pcibios_align_resource(void *data, const struct resource *res,
                if (start & 0x300)
                        start = (start + 0x3ff) & ~0x3ff;
        } else if (res->flags & IORESOURCE_MEM) {
-               start = pci_align_resource(dev, res, empty_res, size, align);
+               start = pci_align_resource(rr, res, empty_res, size, align);
        }
 
        return start;
diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index bcc26785175d..2214347906a6 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -1038,10 +1038,13 @@ static struct agp_memory 
*intel_fake_agp_alloc_by_type(size_t pg_count,
 
 static int intel_alloc_chipset_flush_resource(void)
 {
+       struct pci_resreq_data rr;
        int ret;
+
+       pci_init_pci_resreq_data(&rr, intel_private.bridge_dev);
        ret = pci_bus_alloc_resource(intel_private.bridge_dev->bus, 
&intel_private.ifp_resource, PAGE_SIZE,
                                     PAGE_SIZE, PCIBIOS_MIN_MEM, 0,
-                                    pcibios_align_resource, 
intel_private.bridge_dev);
+                                    pcibios_align_resource, &rr);
 
        return ret;
 }
diff --git a/drivers/gpu/drm/i915/i915_gmch.c b/drivers/gpu/drm/i915/i915_gmch.c
index b0ef6ef577a3..d35097bebc0f 100644
--- a/drivers/gpu/drm/i915/i915_gmch.c
+++ b/drivers/gpu/drm/i915/i915_gmch.c
@@ -38,6 +38,7 @@ static int mchbar_reg(struct drm_i915_private *i915)
 static int
 intel_alloc_mchbar_resource(struct drm_i915_private *i915)
 {
+       struct pci_resreq_data rr;
        u32 temp_lo, temp_hi = 0;
        u64 mchbar_addr;
        int ret;
@@ -55,12 +56,12 @@ intel_alloc_mchbar_resource(struct drm_i915_private *i915)
        /* Get some space for it */
        i915->gmch.mch_res.name = "i915 MCHBAR";
        i915->gmch.mch_res.flags = IORESOURCE_MEM;
+       pci_init_pci_resreq_data(&rr, i915->gmch.pdev);
        ret = pci_bus_alloc_resource(i915->gmch.pdev->bus,
                                     &i915->gmch.mch_res,
                                     MCHBAR_SIZE, MCHBAR_SIZE,
                                     PCIBIOS_MIN_MEM,
-                                    0, pcibios_align_resource,
-                                    i915->gmch.pdev);
+                                    0, pcibios_align_resource, &rr);
        if (ret) {
                drm_dbg(&i915->drm, "failed bus alloc: %d\n", ret);
                i915->gmch.mch_res.start = 0;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b2879a6be5f8..1b7a4469c6ca 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6444,8 +6444,8 @@ static DEFINE_SPINLOCK(resource_alignment_lock);
  * RETURNS: Resource alignment if it is specified.
  *          Zero if it is not specified.
  */
-static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
-                                                       bool *resize)
+resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
+                                                bool *resize)
 {
        int align_order, count;
        resource_size_t align = pcibios_default_alignment();
@@ -6497,6 +6497,7 @@ static resource_size_t 
pci_specified_resource_alignment(struct pci_dev *dev,
        spin_unlock(&resource_alignment_lock);
        return align;
 }
+EXPORT_SYMBOL_GPL(pci_specified_resource_alignment);
 
 static void pci_request_resource_alignment(struct pci_dev *dev, int bar,
                                           resource_size_t align, bool resize)
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 376f09630a4a..441a62807719 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -265,17 +265,21 @@ resource_size_t pci_resource_alignment(const struct 
pci_dev *dev,
  * before res->start if there's enough free space there. This enables
  * tighter packing for resources.
  */
-resource_size_t pci_align_resource(struct pci_dev *dev,
+resource_size_t pci_align_resource(struct pci_resreq_data *rr,
                                   const struct resource *res,
                                   const struct resource *empty_res,
                                   resource_size_t size,
                                   resource_size_t align)
 {
+       struct pci_dev *dev = rr->dev;
        resource_size_t remainder, start_addr;
 
        if (!(res->flags & IORESOURCE_MEM))
                return res->start;
 
+       if (rr->user_align)
+               return res->start;
+
        if (IS_ALIGNED(size, align))
                return res->start;
 
@@ -306,18 +310,21 @@ resource_size_t __weak pcibios_align_resource(void *data,
                                              resource_size_t size,
                                              resource_size_t align)
 {
-       struct pci_dev *dev = data;
+       struct pci_resreq_data *rr = data;
 
-       return pci_align_resource(dev, res, empty_res, size, align);
+       return pci_align_resource(rr, res, empty_res, size, align);
 }
 
 static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
                int resno, resource_size_t size, resource_size_t align)
 {
        struct resource *res = pci_resource_n(dev, resno);
+       struct pci_resreq_data rr;
        resource_size_t min;
        int ret;
 
+       pci_init_pci_resreq_data(&rr, dev);
+
        min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
 
        /*
@@ -329,7 +336,7 @@ static int __pci_assign_resource(struct pci_bus *bus, 
struct pci_dev *dev,
         */
        ret = pci_bus_alloc_resource(bus, res, size, align, min,
                                     IORESOURCE_PREFETCH | IORESOURCE_MEM_64,
-                                    pcibios_align_resource, dev);
+                                    pcibios_align_resource, &rr);
        if (ret == 0)
                return 0;
 
@@ -341,7 +348,7 @@ static int __pci_assign_resource(struct pci_bus *bus, 
struct pci_dev *dev,
             (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) {
                ret = pci_bus_alloc_resource(bus, res, size, align, min,
                                             IORESOURCE_PREFETCH,
-                                            pcibios_align_resource, dev);
+                                            pcibios_align_resource, &rr);
                if (ret == 0)
                        return 0;
        }
@@ -354,7 +361,7 @@ static int __pci_assign_resource(struct pci_bus *bus, 
struct pci_dev *dev,
         */
        if (res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64))
                ret = pci_bus_alloc_resource(bus, res, size, align, min, 0,
-                                            pcibios_align_resource, dev);
+                                            pcibios_align_resource, &rr);
 
        return ret;
 }
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d31a8d107b1e..ea7d75871269 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1217,12 +1217,40 @@ int __must_check pcibios_enable_device(struct pci_dev 
*, int mask);
 /* Architecture-specific versions may override this (weak) */
 char *pcibios_setup(char *str);
 
-/* Used only when drivers/pci/setup.c is used */
+/* Resource assignment request handling */
+/**
+ * struct pci_resreq_data - Data passed to pcibios_align_resource()
+ * @dev: PCI device
+ * @user_align: User provided alignment override (pci=resource_alignment param)
+ */
+struct pci_resreq_data {
+       struct pci_dev *dev;
+       resource_size_t user_align;
+};
+
+resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
+                                                bool *resize);
+/*
+ * TODO: Improve PCI resource assignment interface so that callers outside PCI
+ * core do not need to know about this detail.
+ */
+static inline void pci_init_pci_resreq_data(struct pci_resreq_data *rr,
+                                           struct pci_dev *dev)
+{
+       bool user_aligned;
+
+       memset(rr, 0, sizeof(*rr));
+       rr->dev = dev;
+       rr->user_align = pci_specified_resource_alignment(dev, &user_aligned);
+       if (!user_aligned)
+               rr->user_align = 0;
+}
+
 resource_size_t pcibios_align_resource(void *data, const struct resource *res,
                                       const struct resource *empty_res,
                                       resource_size_t size,
                                       resource_size_t align);
-resource_size_t pci_align_resource(struct pci_dev *dev,
+resource_size_t pci_align_resource(struct pci_resreq_data *rr,
                                   const struct resource *res,
                                   const struct resource *empty_res,
                                   resource_size_t size,
-- 
2.47.3


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