[tip: x86/mm] iommu/sva: Replace pasid_valid() helper with mm_valid_pasid()

[tip-bot2 for Kirill A. Shutemov]

The following commit has been merged into the x86/mm branch of tip:

Commit-ID:     400b9b93441cd4e2fe824a70140f3d5a2a9c802b
Gitweb:        https://git.kernel.org/tip/400b9b93441cd4e2fe824a70140f3d5a2a9c802b
Author:        Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
AuthorDate:    Sun, 12 Mar 2023 14:26:05 +03:00
Committer:     Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Thu, 16 Mar 2023 13:08:40 -07:00

iommu/sva: Replace pasid_valid() helper with mm_valid_pasid()

Kernel has few users of pasid_valid() and all but one checks if the
process has PASID allocated. The helper takes ioasid_t as the input.

Replace the helper with mm_valid_pasid() that takes mm_struct as the
argument. The only call that checks PASID that is not tied to mm_struct
is open-codded now.

This is preparatory patch. It helps avoid ifdeffery: no need to
dereference mm->pasid in generic code to check if the process has PASID.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20230312112612.31869-11-kirill.shutemov%40linux.intel.com
---
 arch/x86/kernel/traps.c   |  6 +++---
 drivers/iommu/iommu-sva.c |  4 ++--
 include/linux/ioasid.h    |  9 ---------
 include/linux/sched/mm.h  |  8 +++++++-
 4 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index d317dc3..8b83d8f 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -671,15 +671,15 @@ static bool try_fixup_enqcmd_gp(void)
 	if (!cpu_feature_enabled(X86_FEATURE_ENQCMD))
 		return false;
 
-	pasid = current->mm->pasid;
-
 	/*
 	 * If the mm has not been allocated a
 	 * PASID, the #GP can not be fixed up.
 	 */
-	if (!pasid_valid(pasid))
+	if (!mm_valid_pasid(current->mm))
 		return false;
 
+	pasid = current->mm->pasid;
+
 	/*
 	 * Did this thread already have its PASID activated?
 	 * If so, the #GP must be from something else.
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index 24bf9b2..4ee2929 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -34,14 +34,14 @@ int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
 
 	mutex_lock(&iommu_sva_lock);
 	/* Is a PASID already associated with this mm? */
-	if (pasid_valid(mm->pasid)) {
+	if (mm_valid_pasid(mm)) {
 		if (mm->pasid < min || mm->pasid >= max)
 			ret = -EOVERFLOW;
 		goto out;
 	}
 
 	pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
-	if (!pasid_valid(pasid))
+	if (pasid == INVALID_IOASID)
 		ret = -ENOMEM;
 	else
 		mm_pasid_set(mm, pasid);
diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
index af1c9d6..836ae09 100644
--- a/include/linux/ioasid.h
+++ b/include/linux/ioasid.h
@@ -40,10 +40,6 @@ void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
 int ioasid_register_allocator(struct ioasid_allocator_ops *allocator);
 void ioasid_unregister_allocator(struct ioasid_allocator_ops *allocator);
 int ioasid_set_data(ioasid_t ioasid, void *data);
-static inline bool pasid_valid(ioasid_t ioasid)
-{
-	return ioasid != INVALID_IOASID;
-}
 
 #else /* !CONFIG_IOASID */
 static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min,
@@ -74,10 +70,5 @@ static inline int ioasid_set_data(ioasid_t ioasid, void *data)
 	return -ENOTSUPP;
 }
 
-static inline bool pasid_valid(ioasid_t ioasid)
-{
-	return false;
-}
-
 #endif /* CONFIG_IOASID */
 #endif /* __LINUX_IOASID_H */
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 2a24361..b69fe7e 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -457,6 +457,11 @@ static inline void mm_pasid_init(struct mm_struct *mm)
 	mm->pasid = INVALID_IOASID;
 }
 
+static inline bool mm_valid_pasid(struct mm_struct *mm)
+{
+	return mm->pasid != INVALID_IOASID;
+}
+
 /* Associate a PASID with an mm_struct: */
 static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid)
 {
@@ -465,13 +470,14 @@ static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid)
 
 static inline void mm_pasid_drop(struct mm_struct *mm)
 {
-	if (pasid_valid(mm->pasid)) {
+	if (mm_valid_pasid(mm)) {
 		ioasid_free(mm->pasid);
 		mm->pasid = INVALID_IOASID;
 	}
 }
 #else
 static inline void mm_pasid_init(struct mm_struct *mm) {}
+static inline bool mm_valid_pasid(struct mm_struct *mm) { return false; }
 static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid) {}
 static inline void mm_pasid_drop(struct mm_struct *mm) {}
 #endif