From: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
Surprisingly or not, disabling a CONFIG option (which is assumed to
be unneeded) may be not so trivial. Especially it is not trivial, when
this CONFIG option is selected by a dozen of other configs. Before the
moment commit 1ccb27143360 ("kconfig: make "Selected by:" and
"Implied by:" readable") popped up in v4.16-rc1, it was an absolute pain
to break down the "Selected by" reverse dependency expression in order
to identify all those configs which select (IOW *do not allow
disabling*) a certain feature (assumed to be not needed).
This patch tries to make one step further by putting at users'
fingertips the revdep top level OR sub-expressions grouped/clustered by
the tristate value they evaluate to. This should allow the users to
directly concentrate on and tackle the _active_ reverse dependencies.
To give some numbers and quantify the complexity of certain reverse
dependencies, assuming commit 617aebe6a97e ("Merge tag
'usercopy-v4.16-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux"), ARCH=arm64
and vanilla arm64 defconfig, here is the top 10 CONFIG options with
the highest amount of top level "||" sub-expressions/tokens that make
up the final "Selected by" reverse dependency expression.
| Config | All revdep | Active revdep |
|-------------------|------------|---------------|
| REGMAP_I2C | 212 | 9 |
| CRC32 | 167 | 25 |
| FW_LOADER | 128 | 5 |
| MFD_CORE | 124 | 9 |
| FB_CFB_IMAGEBLIT | 114 | 2 |
| FB_CFB_COPYAREA | 111 | 2 |
| FB_CFB_FILLRECT | 110 | 2 |
| SND_PCM | 103 | 2 |
| CRYPTO_HASH | 87 | 19 |
| WATCHDOG_CORE | 86 | 6 |
The story behind the above is that users need to visually
review/evaluate 212 expressions which *potentially* select REGMAP_I2C
in order to identify the expressions which *actually* select REGMAP_I2C,
for a particular ARCH and for a particular defconfig used.
To make this experience smoother, change the way reverse dependencies
are displayed to the user from [1] to [2].
[1] Old representation of DMA_ENGINE_RAID:
Selected by:
- AMCC_PPC440SPE_ADMA [=n] && DMADEVICES [=y] && (440SPe || 440SP)
- BCM_SBA_RAID [=m] && DMADEVICES [=y] && (ARM64 [=y] || ...
- FSL_RAID [=n] && DMADEVICES [=y] && FSL_SOC && ...
- INTEL_IOATDMA [=n] && DMADEVICES [=y] && PCI [=y] && X86_64
- MV_XOR [=n] && DMADEVICES [=y] && (PLAT_ORION || ARCH_MVEBU [=y] ...
- MV_XOR_V2 [=y] && DMADEVICES [=y] && ARM64 [=y]
- XGENE_DMA [=n] && DMADEVICES [=y] && (ARCH_XGENE [=y] || ...
- DMATEST [=n] && DMADEVICES [=y] && DMA_ENGINE [=y]
[2] New representation of DMA_ENGINE_RAID:
Selected by [y]:
- MV_XOR_V2 [=y] && DMADEVICES [=y] && ARM64 [=y]
Selected by [m]:
- BCM_SBA_RAID [=m] && DMADEVICES [=y] && (ARM64 [=y] || ...
Selected by [n]:
- AMCC_PPC440SPE_ADMA [=n] && DMADEVICES [=y] && (440SPe || ...
- FSL_RAID [=n] && DMADEVICES [=y] && FSL_SOC && ...
- INTEL_IOATDMA [=n] && DMADEVICES [=y] && PCI [=y] && X86_64
- MV_XOR [=n] && DMADEVICES [=y] && (PLAT_ORION || ARCH_MVEBU [=y] ...
- XGENE_DMA [=n] && DMADEVICES [=y] && (ARCH_XGENE [=y] || ...
- DMATEST [=n] && DMADEVICES [=y] && DMA_ENGINE [=y]
Suggested-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
---
v4->v5:
* 99% based on Masahiro's https://patchwork.kernel.org/patch/10231295/
* Requires Masahiro's https://patchwork.kernel.org/patch/10229545/
* Fixes review findings from Petr Vorel:
* Adds a colon symbol to the end of every "Selected by [y|m|n]"
* Fixes copy-paste error (s/sym->rev_dep.expr/sym->implied.expr/)
leading to segfault when searching for PTP_1588_CLOCK in menuconfig.
* Ignores checkpatch findings:
* "WARNING: line over 80 characters", for the same of readability.
* "ERROR: Please use git commit description style", which seems to
be a checkpatch issue.
v3->v4 (fixed review findings from Ulf):
* Remove redundant default cases in switch constructs.
* Remove gettext _() tokens in str_append() calls.
* Aggregate code repetitions in expr_print_revdep().
v2->v3:
* Switch from reverse dependencies prefixed by their tristate value to
reverse dependencies grouped by the tristate value they evaluate to.
* Skip printing "{Selected,Implied} by [y|m|n]:" if there are no top
level OR tokens/sub-expressions that evaluate to y|m|n (suggested
by Petr).
* Use [1] as template for updating the interface/prototype of
__expr_print() (suggested by Ulf).
v1->v2:
* Don't skip the =n reverse dependency OR tokens, since some users might
still need this information (suggested by Ulf).
* Instead of using "Selected by" for active tokens only, use it for all
OR tokens, but specify the tristate value of each token as prefix
(suggested by Masahiro).
scripts/kconfig/expr.c | 18 ++++++++++++------
scripts/kconfig/expr.h | 3 ++-
scripts/kconfig/menu.c | 10 ++++++----
3 files changed, 20 insertions(+), 11 deletions(-)
diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
index cd3a8f501f38..49376e12fa30 100644
--- a/scripts/kconfig/expr.c
+++ b/scripts/kconfig/expr.c
@@ -1323,19 +1323,25 @@ void expr_gstr_print(struct expr *e, struct gstr *gs)
*/
static void expr_print_revdep(struct expr *e,
void (*fn)(void *, struct symbol *, const char *),
- void *data)
+ void *data, tristate pr_type, const char **title)
{
if (e->type == E_OR) {
- expr_print_revdep(e->left.expr, fn, data);
- expr_print_revdep(e->right.expr, fn, data);
- } else {
+ expr_print_revdep(e->left.expr, fn, data, pr_type, title);
+ expr_print_revdep(e->right.expr, fn, data, pr_type, title);
+ } else if (expr_calc_value(e) == pr_type) {
+ if (*title) {
+ fn(data, NULL, *title);
+ *title = NULL;
+ }
+
fn(data, NULL, " - ");
expr_print(e, fn, data, E_NONE);
fn(data, NULL, "\n");
}
}
-void expr_gstr_print_revdep(struct expr *e, struct gstr *gs)
+void expr_gstr_print_revdep(struct expr *e, struct gstr *gs,
+ tristate pr_type, const char *title)
{
- expr_print_revdep(e, expr_print_gstr_helper, gs);
+ expr_print_revdep(e, expr_print_gstr_helper, gs, pr_type, &title);
}
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index c16e82e302a2..8dbf2a4cdae1 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -310,7 +310,8 @@ struct expr *expr_simplify_unmet_dep(struct expr *e1, struct expr *e2);
void expr_fprint(struct expr *e, FILE *out);
struct gstr; /* forward */
void expr_gstr_print(struct expr *e, struct gstr *gs);
-void expr_gstr_print_revdep(struct expr *e, struct gstr *gs);
+void expr_gstr_print_revdep(struct expr *e, struct gstr *gs,
+ tristate pr_type, const char *title);
static inline int expr_is_yes(struct expr *e)
{
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 7e70be34aa6c..3415fe0bbad7 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -827,14 +827,16 @@ static void get_symbol_str(struct gstr *r, struct symbol *sym,
get_symbol_props_str(r, sym, P_SELECT, _(" Selects: "));
if (sym->rev_dep.expr) {
- str_append(r, _(" Selected by: \n"));
- expr_gstr_print_revdep(sym->rev_dep.expr, r);
+ expr_gstr_print_revdep(sym->rev_dep.expr, r, yes, " Selected by [y]:\n");
+ expr_gstr_print_revdep(sym->rev_dep.expr, r, mod, " Selected by [m]:\n");
+ expr_gstr_print_revdep(sym->rev_dep.expr, r, no, " Selected by [n]:\n");
}
get_symbol_props_str(r, sym, P_IMPLY, _(" Implies: "));
if (sym->implied.expr) {
- str_append(r, _(" Implied by: \n"));
- expr_gstr_print_revdep(sym->implied.expr, r);
+ expr_gstr_print_revdep(sym->implied.expr, r, yes, " Implied by [y]:\n");
+ expr_gstr_print_revdep(sym->implied.expr, r, mod, " Implied by [m]:\n");
+ expr_gstr_print_revdep(sym->implied.expr, r, no, " Implied by [n]:\n");
}
str_append(r, "\n\n");
--
2.16.2
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