quota: merge compat handling back into quotactl

Moving the compat handling into a separate file in commit 5582c76f901d
("quota: split out compat_sys_quotactl support from quota.c") did help
to reduce conditional compilation in the main file, but it makes it hard
to get rid of the last users of compat_alloc_user_space().

Move the type conversion back into the main quota.c file, but do it
directly in the handlers with an in_ia32_syscall() check that avoids
copying every word multiple times.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

6 files changed, 98 insertions, 130 deletions

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 3e9576138baff..7e4140b78aad5 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -142,7 +142,7 @@
 128	i386	init_module		sys_init_module
 129	i386	delete_module		sys_delete_module
 130	i386	get_kernel_syms
-131	i386	quotactl		sys_quotactl			compat_sys_quotactl32
+131	i386	quotactl		sys_quotactl
 132	i386	getpgid			sys_getpgid
 133	i386	fchdir			sys_fchdir
 134	i386	bdflush			sys_bdflush
diff --git a/fs/quota/Kconfig b/fs/quota/Kconfig
index d1ceb76adb71e..b59cd172b5f97 100644
--- a/fs/quota/Kconfig
+++ b/fs/quota/Kconfig
@@ -70,8 +70,3 @@ config QFMT_V2
 config QUOTACTL
 	bool
 	default n
-
-config QUOTACTL_COMPAT
-	bool
-	depends on QUOTACTL && COMPAT_FOR_U64_ALIGNMENT
-	default y
diff --git a/fs/quota/Makefile b/fs/quota/Makefile
index f2b49d0f0287c..9160639daffa7 100644
--- a/fs/quota/Makefile
+++ b/fs/quota/Makefile
@@ -4,5 +4,4 @@ obj-$(CONFIG_QFMT_V1)		+= quota_v1.o
 obj-$(CONFIG_QFMT_V2)		+= quota_v2.o
 obj-$(CONFIG_QUOTA_TREE)	+= quota_tree.o
 obj-$(CONFIG_QUOTACTL)		+= quota.o kqid.o
-obj-$(CONFIG_QUOTACTL_COMPAT)	+= compat.o
 obj-$(CONFIG_QUOTA_NETLINK_INTERFACE)	+= netlink.o
diff --git a/fs/quota/compat.c b/fs/quota/compat.c
deleted file mode 100644
index c305728576193..0000000000000
--- a/fs/quota/compat.c
+++ /dev/null
@@ -1,120 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <linux/syscalls.h>
-#include <linux/compat.h>
-#include <linux/quotaops.h>
-
-/*
- * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
- * and is necessary due to alignment problems.
- */
-struct compat_if_dqblk {
-	compat_u64 dqb_bhardlimit;
-	compat_u64 dqb_bsoftlimit;
-	compat_u64 dqb_curspace;
-	compat_u64 dqb_ihardlimit;
-	compat_u64 dqb_isoftlimit;
-	compat_u64 dqb_curinodes;
-	compat_u64 dqb_btime;
-	compat_u64 dqb_itime;
-	compat_uint_t dqb_valid;
-};
-
-/* XFS structures */
-struct compat_fs_qfilestat {
-	compat_u64 dqb_bhardlimit;
-	compat_u64 qfs_nblks;
-	compat_uint_t qfs_nextents;
-};
-
-struct compat_fs_quota_stat {
-	__s8		qs_version;
-	__u16		qs_flags;
-	__s8		qs_pad;
-	struct compat_fs_qfilestat	qs_uquota;
-	struct compat_fs_qfilestat	qs_gquota;
-	compat_uint_t	qs_incoredqs;
-	compat_int_t	qs_btimelimit;
-	compat_int_t	qs_itimelimit;
-	compat_int_t	qs_rtbtimelimit;
-	__u16		qs_bwarnlimit;
-	__u16		qs_iwarnlimit;
-};
-
-COMPAT_SYSCALL_DEFINE4(quotactl32, unsigned int, cmd,
-		       const char __user *, special, qid_t, id,
-		       void __user *, addr)
-{
-	unsigned int cmds;
-	struct if_dqblk __user *dqblk;
-	struct compat_if_dqblk __user *compat_dqblk;
-	struct fs_quota_stat __user *fsqstat;
-	struct compat_fs_quota_stat __user *compat_fsqstat;
-	compat_uint_t data;
-	u16 xdata;
-	long ret;
-
-	cmds = cmd >> SUBCMDSHIFT;
-
-	switch (cmds) {
-	case Q_GETQUOTA:
-		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
-		compat_dqblk = addr;
-		ret = kernel_quotactl(cmd, special, id, dqblk);
-		if (ret)
-			break;
-		if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
-			get_user(data, &dqblk->dqb_valid) ||
-			put_user(data, &compat_dqblk->dqb_valid))
-			ret = -EFAULT;
-		break;
-	case Q_SETQUOTA:
-		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
-		compat_dqblk = addr;
-		ret = -EFAULT;
-		if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
-			get_user(data, &compat_dqblk->dqb_valid) ||
-			put_user(data, &dqblk->dqb_valid))
-			break;
-		ret = kernel_quotactl(cmd, special, id, dqblk);
-		break;
-	case Q_XGETQSTAT:
-		fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
-		compat_fsqstat = addr;
-		ret = kernel_quotactl(cmd, special, id, fsqstat);
-		if (ret)
-			break;
-		ret = -EFAULT;
-		/* Copying qs_version, qs_flags, qs_pad */
-		if (copy_in_user(compat_fsqstat, fsqstat,
-			offsetof(struct compat_fs_quota_stat, qs_uquota)))
-			break;
-		/* Copying qs_uquota */
-		if (copy_in_user(&compat_fsqstat->qs_uquota,
-			&fsqstat->qs_uquota,
-			sizeof(compat_fsqstat->qs_uquota)) ||
-			get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
-			put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
-			break;
-		/* Copying qs_gquota */
-		if (copy_in_user(&compat_fsqstat->qs_gquota,
-			&fsqstat->qs_gquota,
-			sizeof(compat_fsqstat->qs_gquota)) ||
-			get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
-			put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
-			break;
-		/* Copying the rest */
-		if (copy_in_user(&compat_fsqstat->qs_incoredqs,
-			&fsqstat->qs_incoredqs,
-			sizeof(struct compat_fs_quota_stat) -
-			offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
-			get_user(xdata, &fsqstat->qs_iwarnlimit) ||
-			put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
-			break;
-		ret = 0;
-		break;
-	default:
-		ret = kernel_quotactl(cmd, special, id, addr);
-	}
-	return ret;
-}
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 5444d3c4d93f3..9270174534fdc 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -194,6 +194,22 @@ static void copy_to_if_dqblk(struct if_dqblk *dst, struct qc_dqblk *src)
 	dst->dqb_valid = QIF_ALL;
 }
 
+/*
+ * This code works only for 32 bit quota tools over 64 bit x86 kernels
+ * and is necessary due to alignment problems.
+ */
+struct compat_if_dqblk {
+	compat_u64 dqb_bhardlimit;
+	compat_u64 dqb_bsoftlimit;
+	compat_u64 dqb_curspace;
+	compat_u64 dqb_ihardlimit;
+	compat_u64 dqb_isoftlimit;
+	compat_u64 dqb_curinodes;
+	compat_u64 dqb_btime;
+	compat_u64 dqb_itime;
+	compat_uint_t dqb_valid;
+};
+
 static int quota_getquota(struct super_block *sb, int type, qid_t id,
 			  void __user *addr)
 {
@@ -211,8 +227,19 @@ static int quota_getquota(struct super_block *sb, int type, qid_t id,
 	if (ret)
 		return ret;
 	copy_to_if_dqblk(&idq, &fdq);
+
+#ifdef CONFIG_IA32_EMULATION
+	if (in_ia32_syscall()) {
+		if (copy_to_user(addr, &idq, sizeof(struct compat_if_dqblk)))
+			return -EFAULT;
+
+		return 0;
+	}
+#endif
+
 	if (copy_to_user(addr, &idq, sizeof(idq)))
 		return -EFAULT;
+
 	return 0;
 }
 
@@ -277,6 +304,14 @@ static int quota_setquota(struct super_block *sb, int type, qid_t id,
 	struct if_dqblk idq;
 	struct kqid qid;
 
+#ifdef CONFIG_IA32_EMULATION
+	if (in_ia32_syscall()) {
+		if (copy_from_user(&idq, addr, sizeof(struct compat_if_dqblk)))
+			return -EFAULT;
+
+		return 0;
+	} else
+#endif
 	if (copy_from_user(&idq, addr, sizeof(idq)))
 		return -EFAULT;
 	if (!sb->s_qcop->set_dqblk)
@@ -382,6 +417,27 @@ static int quota_getstate(struct super_block *sb, int type,
 	return 0;
 }
 
+/* XFS structures */
+struct compat_fs_qfilestat {
+	compat_u64 qfs_ino;
+	compat_u64 qfs_nblks;
+	compat_uint_t qfs_nextents;
+};
+
+struct compat_fs_quota_stat {
+	__s8		qs_version;
+	__u16		qs_flags;
+	__s8		qs_pad;
+	struct compat_fs_qfilestat	qs_uquota;
+	struct compat_fs_qfilestat	qs_gquota;
+	compat_uint_t	qs_incoredqs;
+	compat_int_t	qs_btimelimit;
+	compat_int_t	qs_itimelimit;
+	compat_int_t	qs_rtbtimelimit;
+	__u16		qs_bwarnlimit;
+	__u16		qs_iwarnlimit;
+};
+
 static int quota_getxstate(struct super_block *sb, int type, void __user *addr)
 {
 	struct fs_quota_stat fqs;
@@ -390,9 +446,48 @@ static int quota_getxstate(struct super_block *sb, int type, void __user *addr)
 	if (!sb->s_qcop->get_state)
 		return -ENOSYS;
 	ret = quota_getstate(sb, type, &fqs);
-	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_IA32_EMULATION
+	if (in_ia32_syscall()) {
+		struct compat_fs_quota_stat cfqs;
+
+		memset(&cfqs, 0, sizeof(cfqs));
+
+		cfqs = (struct compat_fs_quota_stat) {
+			.qs_version	 = fqs.qs_version,
+			.qs_flags	 = fqs.qs_flags,
+			.qs_pad		 = fqs.qs_pad,
+			.qs_uquota	 = {
+			       .qfs_ino		= fqs.qs_uquota.qfs_ino,
+			       .qfs_nblks	= fqs.qs_uquota.qfs_nblks,
+			       .qfs_nextents	= fqs.qs_uquota.qfs_nextents,
+			},
+			.qs_gquota	 = {
+			       .qfs_ino		= fqs.qs_gquota.qfs_ino,
+			       .qfs_nblks	= fqs.qs_gquota.qfs_nblks,
+			       .qfs_nextents	= fqs.qs_gquota.qfs_nextents,
+			},
+			.qs_incoredqs	 = fqs.qs_incoredqs,
+			.qs_btimelimit	 = fqs.qs_btimelimit,
+			.qs_itimelimit	 = fqs.qs_itimelimit,
+			.qs_rtbtimelimit = fqs.qs_rtbtimelimit,
+			.qs_bwarnlimit	 = fqs.qs_bwarnlimit,
+			.qs_iwarnlimit	 = fqs.qs_iwarnlimit,
+		};
+
+		if (copy_to_user(addr, &cfqs, sizeof(cfqs)))
+			return -EFAULT;
+
+		return 0;
+	}
+#endif
+
+	if (copy_to_user(addr, &fqs, sizeof(fqs)))
 		return -EFAULT;
-	return ret;
+
+	return 0;
 }
 
 static int quota_getstatev(struct super_block *sb, int type,
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 4d59775ea79c1..c925d1e1777ef 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -369,7 +369,6 @@ COND_SYSCALL_COMPAT(fanotify_mark);
 /* x86 */
 COND_SYSCALL(vm86old);
 COND_SYSCALL(modify_ldt);
-COND_SYSCALL_COMPAT(quotactl32);
 COND_SYSCALL(vm86);
 COND_SYSCALL(kexec_file_load);